I found this link is quite informative
https://www.cloudbees.com/blog/better-integration-between-jenkins-and-github-github-jenkins-plugin to elaborate the details. However, it seems that it does not reflect the administrative UI for Jenkin 2.7. I have my github plugin installed.
Specifically, "In the GitHub Web Hook section select the Let Jenkins auto-manage hook URLs option.". I can't find the Github Web Hook section in my administrative UI.
Is there an updated instruction page for this subject?