Well, start with the play docs [1]; from there, yeah, you have to hunt around. Play's more of a framework for building frameworks than an out-of-the-box batteries included web framework like Rails, Django, etc. It provides the building blocks to create anything, the rest is up to you.

When I was learning Play I found digging through the sources to be immensely useful, not only for learning the framework itself, but for learning Scala as well.

[1] https://www.playframework.com/documentation/2.6.x/ScalaHome