When I started out, I used slax on a crappy laptop via a USB stick. If you have a look at their modules, and how they integrate into the system at boot, you can learn the basics of file locations. Plus it doesn't matter if you break it, just flash another iso and try different desktop environments, package managers, distros etc.
Also try building a driver for an old webcam or something. You might want to do this once you're a bit more familiar tho(forums are great for help with this). If you do get it working, you can post it and you'll have contributed to help someone else.
We were all newbies at some point, so if someone is trying to piss you off, just ignore them. Don't think you'll find that here tho. Remember, if you're not breaking things every so often, you don't learn.
Have fun, and don't forget to laugh at apple users. Lol