Lost in Fiori. Where do I get valid information?

I just returned from a training on SAP Fiori App development. I feel totally lost...

Surely due to the fact that I coded for decades in ABAP, I do not seem to be able to get into the Fiori logic. All those calls to mysterial modules of even more mysterial classes. And no way to double click on the module name to see what's happening there. In the training, we did not even make it to put a simple list coming from an odata service on the screen. Not even the trainer was able to find the bug....

Where can I get valid information that helps me understanding all this stuff (especially how to access odata services)?