I have been where you are, with a much less advanced version of the program when I started and no one bothered to even help me. I read the manual which explains runtime structure and how to install content and followed that, often actually manually placing things until I understood what was what. The manual literally answers ' what is a runtime' and ' what is under it in all of those folders'.

I dont want to sound snarky or unhelpful, but looking in an already supplied manual is the first step.