EventLoop is the basic framework for running jobs in AnalysisBase. If you are new to EventLoop, take a look at the beginner’s tutorial which walks you step by step through setting up a basic EventLoop job and run it, as well as a lot of the basic tools you may want to use inside your job.
Once you are done with the tutorial and feel comfortable with the basics you may want to take a look at the subsequent pages for more advanced topics that seemed to specialized for the beginner’s tutorial. Note that this documentation isn’t as well maintained as the tutorial, so you may find some sections that are more outdated or don’t implement all the latest recommendations.