Basic overview of core concepts to do a simple checkout and build using a Jenkinsfile. This should be next step after a user has created their first "Hello World" example. This should be the recommended job for new jobs moving forward because users can always have a single Jenkinsfile in Master but skip other branches.
At the end of this section the reader should know what a Jenkinsfile is and how to use it. They should also understand Organization Folders and how this will affect Pull Requests. We need to stress that most Pipeline Jobs should be Multibranch or Organization Folders to take advantage of branch strategies and pull requests.
Topics: Jenkinsfile, Multibranch jobs, Organization Folders, Folder Computation (hate that word), job triggers, polling, Branch Sources, Pull Requests