I've found that it really helps to start with the high-level overview of Phoenix if you don't have experience with 'Railsy' frameworks. Then look at the 'magic

I've found that it really helps to start with the high-level overview of Phoenix if you don't have experience with 'Railsy' frameworks. Then look at the 'magic' bits. <app_name>_web.ex is an important one, and the view/template distinction can be a bit confusing at first. From there I suppose endpoint.ex covers pretty much all the rest of it (and then hands things off to router.ex). With Rails I was always uncomfortable that I couldn't quite follow or understand the path taken through my codebase, but with the exception of a few 'magic' things, Phoenix is wonderfully transparent in this regard.