Debian + Gnome. The debian wiki is full of great documentation. If you prefer watching, there's so many great (and not-so-great) courses on YouTube. I personally found tutoriaLinux's series helpful. Please understand that is merelyy what helped me at that point in my journey not necessarily the best tutorial series for you or anyone else.

My biggest tip is, regardless of the teacher or the lesson: follow along. Learn by doing, not by watching someone else doing. If you find yourself thinking anything like "couldn't I have done this" or "but what would happen if I changed this parameter": Do It. Try it out. Seee what happens.

Coincidentally, my second biggest tip is: use a test environment to do anything that you don't fully understand. Even if it's only a new folder with a bunch of empty files to practice file manipulation commands, it's way better than losing your important files. Anything that affects software configuration should be backed up first, anything that affects the OS should be tested in a VM