add how-to section for usage

README.md

@@ -6,6 +6,20 @@ The action pushes to an Azure Storage Container, and assumed an existing reverse
 
 By default, it will also purge the provided CDN path.
 
+## How-to
+These instructions apply only to NGINX GitHub doc repositories.
+1. Navigate to the actions section of your repository, for example https://github.com/yourOrg/yourRepo/actions
+1. On the left side of the page, select Build and deploy (docs). If you don't see this option, follow the [Caller Example](#caller-example).
+![Build and deploy (docs)](/images/build-and-deploy.png "Build and deploy (docs)")
+1. On the right side, you will see a Run workflow button.
+![Run Workflow](/images/run-workflow.png "Run Workflow")
+1. Select Run workflow. This opens a menu which lets you select the branch you want to build, and which environment you'd like to deploy to
+1. The preview environment generates a custom URL for your preferred branch, and will be available in the workflow output.
+All builds, regardless of environment, prints an URL to the summary.
+![Summary](/images/summary.png "Summary")
+
+_note: autodeploy from branch is currently in progress. This docs will be updated when available._
+
 ## Usage
 
 ### Security considerations