The trick is not to try figure it out. Look it up.
I did, even downloaded the official manual. There are some things that were not explained in the manual, like how to take inventory items from a container, etc. IIRC, it's a somewhat strange system, I think you had to press a couple keys for many of the functions. I always remap keys for every game as I use a
Nostromo, and in all the Gothic and Risen games I seem to recall there were usually a couple of keys that were not possible to remap.
At any rate, I only played for about an hour, so I might go back and try it again in the future. By the time I got it installed properly with whatever patches you need so it can run on a modern computer without crashing on startup, I was probably ready to give up too quickly.
I bought gothic 1, 2, 3 and 4 together in a package deal on Steam. Gothic 4 is really bad, don't play it. It's the only game I played where I kept thinking it was going to get better and played the entire game but hated it.
I skipped gothic 2 and tried Gothic 3 for a little while, but there was some sort of texture issue I couldn't resolve with G3. Will probably go back and try Gothic 3 again at some point. I later bought Risen during a Steam sale and had a weird bug where my character's head kept disappearing, I think I fixed that, but later on an NPC's head disappeared and never figured out what the problem was.