Update CONTRIBUTING.md and add sdk/CONTRIBUTING.md (#2693)

* Update CONTRIBUTING.md

* Add CODEOWNERS check to pull request template

* Update CONTRIBUTING.md Goals section

* Update CONTRIBUTING.md Goals section

* Fix typos

* Update CONTRIBUTING.md Non-goals section

* Update wording for Non-goals

* Update CONTRIBUTING.md additional resources

* Update main contributing guide

* Add SDK contributing guide

* Update pull request template

* Update pull request template

* Remove pull request merge/approval section

* Add notice about code samples update timing

* Add link to template

.github/PULL_REQUEST_TEMPLATE.md

@@ -4,7 +4,10 @@
 # Checklist
 
 
-- [ ] I have read the [contribution guidelines](https://github.com/Azure/azureml-examples/blob/main/CONTRIBUTING.md)
+- [ ] I have read the contribution guidelines.
+  - [General](https://github.com/Azure/azureml-examples/blob/main/CONTRIBUTING.md)
+  - [SDK](https://github.com/Azure/azureml-examples/blob/main/sdk/CONTRIBUTING.md)
+  - [CLI](https://github.com/Azure/azureml-examples/blob/main/cli/CONTRIBUTING.md)
 - [ ] I have coordinated with the docs team (mldocs@microsoft.com) if this PR deletes files or changes any file names or file extensions.
 - [ ] Pull request includes test coverage for the included changes.
 - [ ] This notebook or file is added to the [CODEOWNERS](https://github.com/Azure/azureml-examples/blob/main/.github/CODEOWNERS) file, pointing to the author or the author's team.

CONTRIBUTING.md

@@ -29,13 +29,13 @@ This repository contains notebooks and sample code that demonstrate how to devel
 
 ## Issues
 
-All forms of feedback are welcome through [issues](https://github.com/Azure/azureml-examples/issues/new/choose) - please follow the pre-defined templates where applicable.
+All forms of feedback are welcome through [issues](https://github.com/Azure/azureml-examples/issues/new/choose). Please follow the pre-defined templates where applicable.
 
 ## Repository structure
 
 Azure Machine Learning has multiple developer experiences. The subdirectories at the root of the repo correspond to a developer experience, with the slight exception of `notebooks`.
 
-The `notebooks` directory is intended for iterative, interactive code development examples such as exploratory data anlysis or querying logged metrics.
+The `notebooks` directory is intended for iterative, interactive code development examples such as exploratory data analysis or querying logged metrics.
 
 ## Pull Requests
 
@@ -67,30 +67,33 @@ Also if adding new examples or changing existing descriptions, run the `readme.p
 python readme.py
 ```
 
-This will also generate a GitHub Actions workflow file for any new examples in the `.github/workflows` directory (with exceptions) to test the examples on the PR and regularly after merging into the main branch. PRs which edit existing examples will generally trigger a workflow to test the example. See the specific contributing guidelines for the subdirectories for further details. If the new notebook uses compute cluster, please add it to the `sdk/python/notebooks_config.ini` file so the compute clusters will be properly deleted after notebook run was finished. Create a section with the notebook name and add the option `COMPUTE_NAMES` with the compute cluster name. 
+This will also generate a GitHub Actions workflow file for any new examples in the `.github/workflows` directory (with exceptions) to test the examples on the PR and regularly after merging into the main branch. PRs which edit existing examples will generally trigger a workflow to test the example. See the specific contributing guidelines for the subdirectories for further details. If the new notebook uses a compute cluster, please add it to the `sdk/python/notebooks_config.ini` file so the compute clusters will be properly deleted after notebook run was finished. Create a section with the notebook name and add the option `COMPUTE_NAMES` with the compute cluster name. 
 
 ### Discoverability
 
 Examples in this repository can be indexed in the [Microsoft code samples browser](https://docs.microsoft.com/samples), enabling organic discoverability. To accomplish this:
 
-- add an excellent `README.md` file in the example directory
+- add an excellent `README.md` file in the example directory noting the overview, objective, and estimated runtime. (Note than estimated runtimes should not exceed 30 minutes).
 - add required YAML frontmatter at the top of the `README.md`
 
-The YAML frontmatter is this:
+The YAML frontmatter format looks like this:
 
 ```YAML
 ---
 page_type: sample
 languages:
 - azurecli
-- python
+- language1
+- language2
 products:
 - azure-machine-learning
 description: Example description.
 ---
 ```
 
-**Edit the description** and update the languages as needed.
+Edit the description and update the languages as needed.
+
+The Code Samples browser content is updated twice a week, so it may take a few days for your changes to be reflected.
 
 ### Other resources
 * [CLI contributing guide.](cli/CONTRIBUTING.md)

sdk/CONTRIBUTING.md

@@ -0,0 +1,7 @@
+[Azure/azureml-examples overall contributing guide.](../CONTRIBUTING.md)
+
+## Adding a new SDK sample
+
+All SDK samples should be provided as Jupyter notebooks. Please follow the [pre-defined notebook template](../infra/templates/notebook_template.ipynb) and the instructions on [the main CONTRIBUTING page](../CONTRIBUTING.md).
+
+**Important:** PRs from forks of this repository are likely to fail automated workflows due to access to secrets. PRs from forks will be considered but may experience additional delay for testing.