What are some reverse engineering methods? Thread

So I wanna pick up modding games as a hobby and I want to start with CubeWorld because I like the game and I think it's a game that's very compatible with mods and it would benefit alot from them.
As of right now the only working modding for the game that I've found is for replacing moddels / sounds / pictures. But no gameplay mods like, new classes, new pets, even new items (you can only replace model for existing ones), etc.
So digging up on the internet I came to the conclusion (I may be wrong here) that to do this kind of mods some knowledge of the source code is necessary and since they havent released the source code some reverse engineering is needed to get it.
So far what I've come up with is that the game is written in c++ (may be wrong here too, any way to find out?) and that a way to reverse engineer it is by code caving wich a found a tutorial here
And finally the purpose of the post, hat are some reverse engineering methods besides code caving? I'm assuming there are more so, are some harder than others? Does the fact that the game is written in c++ matter for the method?
Would appreciate tutorials and that kind of stuff.

Sadly, you have to dig into one of those hard, old-fashioned ways, assembly/disassembly, hex editor, etc. Those codecaves may also work, but it depends on the game. Modding is all about experimenting, and reverse-engineering (for modding purposes naturally, not hacking or stealing) is a hardcore version of modding.

It also depends on the game and the method you choose to reverse-engineer or add stuff to it. You can even use a notepad-like text editor to change path strings to make the EXE file read data from another location (if you can find any in the exe file) as long as you keep the original number of characters in the modified strings. Also, if you cannot find any soft-coded files anywhere (whether they would be packaged or loose, not packed in any archive format), you can expect everything to be hardcoded and that is a long, lonely road to mod the game code properly. (Old Command & Conquer games have been hacked for modding purposes for many years and that really takes a ton of effort and passion.)