Update Helix.md with additional guidance about queues/checkin expectations (#23486)

docs/Helix.md

@@ -20,12 +20,23 @@ This will restore, and then publish all the test project including some bootstra
 
 - Required queues: Windows10, OSX, Ubuntu1604 
 - Full queue matrix: Windows[7, 81, 10], Ubuntu[1604, 1804, 2004], Centos7, Debian[8,9], Redhat7, Fedora28, Arm64 (Win10, Debian9)
+- The queues are defined in [Helix.Common.props](https://github.com/dotnet/aspnetcore/blob/master/eng/targets/Helix.Common.props)
 
-aspnetcore-ci runs non quarantined tests against the required helix queues as a required PR check and all builds on all branches.
+[aspnetcore-ci](https://dev.azure.com/dnceng/public/_build?definitionId=278) runs non quarantined tests against the required helix queues as a required PR check and all builds on all branches.
 
-aspnetcore-quarantined-tests runs only quarantined tests against the required queues only on master every 4 hours.
+[aspnetcore-helix-matrix](https://dev.azure.com/dnceng/public/_build?definitionId=837) runs non quarantined tests against all queues twice a day only on public master.
+
+[aspnetcore-quarantined-pr](https://dev.azure.com/dnceng/public/_build?definitionId=869) runs only quarantined tests against the required queues on PRs and on master every 4 hours.
+
+[aspnetcore-quarantined-tests](https://dev.azure.com/dnceng/public/_build?definitionId=331) runs only quarantined tests against all queues only on public master once a day at 11 PM.
+
+You can always manually queue pipeline runs by clicking on the link to the pipeline -> Run Pipeline -> select your branch/tag and commit
+
+## Checkin process expectations
+
+- The normal PR process has aspnetcore-ci will ensure that the required queues are green.
+- If your changes are likely to have cross platform impact that would affect more than the required queues, you should kick off a manual aspnetcore-helix-matrix pipeline run against your branch before merging your PR. Even though aspnetcore-helix-matrix is not a required checkin gate, if your changes break this pipeline, you must either immediately revert your changes, or quarantine the test, its never ok to leave this pipeline in a broken state.
 
-aspnetcore-helix-matrix runs non quarantined tests against all queues twice a day only on public master.
 
 ## How do I look at the results of a helix run on Azure Pipelines?