Add more info about how GitHub-hosted runners are used (#27489)

Co-authored-by: Lucas Costi <lucascosti@users.noreply.github.com>

content/actions/using-github-hosted-runners/about-github-hosted-runners.md

@@ -9,6 +9,7 @@ redirect_from:
   - /actions/reference/virtual-environments-for-github-hosted-runners
   - /actions/reference/software-installed-on-github-hosted-runners
   - /actions/reference/specifications-for-github-hosted-runners
+miniTocMaxHeadingLevel: 3
 versions:
   fpt: '*'
   ghes: '*'
@@ -19,36 +20,70 @@ shortTitle: GitHub-hosted runners
 {% data reusables.actions.enterprise-beta %}
 {% data reusables.actions.enterprise-github-hosted-runners %}
 
-## About {% data variables.product.prodname_dotcom %}-hosted runners
+## Overview of {% data variables.product.prodname_dotcom %}-hosted runners
 
-A {% data variables.product.prodname_dotcom %}-hosted runner is a virtual machine hosted by {% data variables.product.prodname_dotcom %} with the {% data variables.product.prodname_actions %} runner application installed. {% data variables.product.prodname_dotcom %} offers runners with Linux, Windows, and macOS operating systems.
+Runners are the machines that execute jobs in a {% data variables.product.prodname_actions %} workflow. For example, a runner can clone your repository locally, install testing software, and then run commands that evaluate your code. 
 
-When you use a {% data variables.product.prodname_dotcom %}-hosted runner, machine maintenance and upgrades are taken care of for you. You can run workflows directly on the virtual machine or in a Docker container.
+{% data variables.product.prodname_dotcom %} provides runners that you can use to run your jobs, or you can [host your own runners](/actions/hosting-your-own-runners/about-self-hosted-runners). Each {% data variables.product.prodname_dotcom %}-hosted runner is a new virtual machine (VM) hosted by {% data variables.product.prodname_dotcom %} with the runner application and other tools preinstalled, and is available with Ubuntu Linux, Windows, or macOS operating systems. When you use a {% data variables.product.prodname_dotcom %}-hosted runner, machine maintenance and upgrades are taken care of for you.
-
-You can specify the runner type for each job in a workflow. Each job in a workflow executes in a fresh instance of the virtual machine. All steps in the job execute in the same instance of the virtual machine, allowing the actions in that job to share information using the filesystem.
 
 {% ifversion not ghes %}
 
+## Using a {% data variables.product.prodname_dotcom %}-hosted runner
+
+To use a {% data variables.product.prodname_dotcom %}-hosted runner, create a job and use `runs-on` to specify the type of runner that will process the job, such as `ubuntu-latest`, `windows-latest`, or `macos-latest`. For the full list of runner types, see "[Supported runners and hardware resources](/actions/using-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources)."
+
+When the job begins, {% data variables.product.prodname_dotcom %} automatically provisions a new VM for that job. All steps in the job execute on the VM, allowing the steps in that job to share information using the runner's filesystem. You can run workflows directly on the VM or in a Docker container. When the job has finished, the VM is automatically decommissioned.
+
+The following diagram demonstrates how two jobs in a workflow are executed on two different {% data variables.product.prodname_dotcom %}-hosted runners. 
+
+![Two runners processing separate jobs](/assets/images/help/images/overview-github-hosted-runner.png)
+
+The following example workflow has two jobs, named `Run-npm-on-Ubuntu` and `Run-PSScriptAnalyzer-on-Windows`. When this workflow is triggered, {% data variables.product.prodname_dotcom %} provisions a new virtual machine for each job. 
+
+- The job named `Run-npm-on-Ubuntu` is executed on a Linux VM, because the job's `runs-on:` specifies `ubuntu-latest`. 
+- The job named `Run-PSScriptAnalyzer-on-Windows` is executed on a Windows VM, because the job's `runs-on:` specifies `windows-latest`. 
+
+```yaml{:copy}
+name: Run commands on different operating systems
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  Run-npm-on-Ubuntu:
+    name: Run npm on Ubuntu
+    runs-on: ubuntu-latest
+    steps:
+      - uses: {% data reusables.actions.action-checkout %}
+      - uses: {% data reusables.actions.action-setup-node %}
+        with:
+          node-version: '14'
+      - run: npm help
+
+  Run-PSScriptAnalyzer-on-Windows:
+    name: Run PSScriptAnalyzer on Windows
+    runs-on: windows-latest
+    steps:
+      - uses: {% data reusables.actions.action-checkout %}
+      - name: Install PSScriptAnalyzer module
+        shell: pwsh
+        run: |
+          Set-PSRepository PSGallery -InstallationPolicy Trusted
+          Install-Module PSScriptAnalyzer -ErrorAction Stop
+      - name: Get list of rules
+        shell: pwsh
+        run: |
+          Get-ScriptAnalyzerRule
+```
+
+While the job runs, the logs and output can be viewed in the {% data variables.product.prodname_dotcom %} UI:
+
+![Job output in the Actions UI](/assets/images/help/repository/actions-runner-output.png)
+
 {% data reusables.actions.runner-app-open-source %}
 
-### Cloud hosts for {% data variables.product.prodname_dotcom %}-hosted runners
-
-{% data variables.product.prodname_dotcom %} hosts Linux and Windows runners on Standard_DS2_v2 virtual machines in Microsoft Azure with the {% data variables.product.prodname_actions %} runner application installed. The {% data variables.product.prodname_dotcom %}-hosted runner application is a fork of the Azure Pipelines Agent. Inbound ICMP packets are blocked for all Azure virtual machines, so ping or traceroute commands might not work. For more information about the Standard_DS2_v2 machine resources, see "[Dv2 and DSv2-series](https://docs.microsoft.com/azure/virtual-machines/dv2-dsv2-series#dsv2-series)" in the Microsoft Azure documentation.
-
-{% data variables.product.prodname_dotcom %} hosts macOS runners in {% data variables.product.prodname_dotcom %}'s own macOS Cloud.
-
-### Workflow continuity for {% data variables.product.prodname_dotcom %}-hosted runners
-
-{% data reusables.actions.runner-workflow-continuity %}
-
-In addition, if the workflow run has been successfully queued, but has not been processed by a {% data variables.product.prodname_dotcom %}-hosted runner within 45 minutes, then the queued workflow run is discarded.
-
-### Administrative privileges of {% data variables.product.prodname_dotcom %}-hosted runners
-
-The Linux and macOS virtual machines both run using passwordless `sudo`. When you need to execute commands or install tools that require more privileges than the current user, you can use `sudo` without needing to provide a password. For more information, see the "[Sudo Manual](https://www.sudo.ws/man/1.8.27/sudo.man.html)."
-
-Windows virtual machines are configured to run as administrators with User Account Control (UAC) disabled. For more information, see "[How User Account Control works](https://docs.microsoft.com/windows/security/identity-protection/user-account-control/how-user-account-control-works)" in the Windows documentation.
-
 ## Supported runners and hardware resources
 
 Hardware specification for Windows and Linux virtual machines:
@@ -98,6 +133,24 @@ If there is a tool that you'd like to request, please open an issue at [actions/
 
 You can install additional software on {% data variables.product.prodname_dotcom %}-hosted runners. For more information, see "[Customizing GitHub-hosted runners](/actions/using-github-hosted-runners/customizing-github-hosted-runners)".
 
+## Cloud hosts used by {% data variables.product.prodname_dotcom %}-hosted runners
+
+{% data variables.product.prodname_dotcom %} hosts Linux and Windows runners on `Standard_DS2_v2` virtual machines in Microsoft Azure with the {% data variables.product.prodname_actions %} runner application installed. The {% data variables.product.prodname_dotcom %}-hosted runner application is a fork of the Azure Pipelines Agent. Inbound ICMP packets are blocked for all Azure virtual machines, so ping or traceroute commands might not work. For more information about the `Standard_DS2_v2` resources, see "[Dv2 and DSv2-series](https://docs.microsoft.com/azure/virtual-machines/dv2-dsv2-series#dsv2-series)" in the Microsoft Azure documentation.
+
+{% data variables.product.prodname_dotcom %} hosts macOS runners in {% data variables.product.prodname_dotcom %}'s own macOS Cloud.
+
+## Workflow continuity
+
+{% data reusables.actions.runner-workflow-continuity %}
+
+In addition, if the workflow run has been successfully queued, but has not been processed by a {% data variables.product.prodname_dotcom %}-hosted runner within 45 minutes, then the queued workflow run is discarded.
+
+## Administrative privileges
+
+The Linux and macOS virtual machines both run using passwordless `sudo`. When you need to execute commands or install tools that require more privileges than the current user, you can use `sudo` without needing to provide a password. For more information, see the "[Sudo Manual](https://www.sudo.ws/man/1.8.27/sudo.man.html)."
+
+Windows virtual machines are configured to run as administrators with User Account Control (UAC) disabled. For more information, see "[How User Account Control works](https://docs.microsoft.com/windows/security/identity-protection/user-account-control/how-user-account-control-works)" in the Windows documentation.
+
 ## IP addresses
 
 {% note %}