For more information about publishing sources, see "About GitHub Pages."
Choosing a publishing source
Before you configure a publishing source, make sure the branch you want to use as your publishing source already exists in your repository.
-  On GitHub Enterprise Server, navigate to your site's repository. 
-  Under your repository name, click Settings.  
-  In the left sidebar, click Pages.  
-  Under "GitHub Pages", use the None or Branch drop-down menu and select a publishing source.  
-  Optionally, use the drop-down menu to select a folder for your publishing source.  
-  Click Save.  
Troubleshooting publishing problems with your GitHub Pages site
Note: If your site has not published automatically, make sure someone with admin permissions and a verified email address has pushed to the publishing source.
If you choose the docs folder on any branch as your publishing source, then later remove the /docs folder from that branch in your repository, your site won't build and you'll get a page build error message for a missing /docs folder. For more information, see "Troubleshooting Jekyll build errors for GitHub Pages sites."