How do I get WebMatrix to talk to my GitHub Repository?

I've followed instructions for installing Git with WebMatrix

https://www.microsoft.com/Web/webmatrix/git.aspx

However I can't see the context menus for Git when I right click on files and clicking Commit or Branch in the Source Control tab doesn't update my GitHub - it seems to be updating something - but it isn't the repository in https://github.com.

What do I need to do to get it working?

The Help File link in WebMatrix 3 for using Git gets a "page not found" error

https://www.microsoft.com/web/post/how-to-use-git-in-webmatrix