I don't have experience with reverse engineering either, but that sounds like the right way to do it.
Apart from decompiling and trying to understand from the disassembly (or however IDA represents it), it could also help to (additionally) run the game in a debugger to see what happens at runtime (maybe IDA/Ghidra support that as well, no idea)
Apart from decompiling and trying to understand from the disassembly (or however IDA represents it), it could also help to (additionally) run the game in a debugger to see what happens at runtime (maybe IDA/Ghidra support that as well, no idea)