Sorry to say but if you still dont understand a tool/concept after four years than it is time to move on and stop to waste your time.
If you want to continue than you should ask yourself what your main goal is. Is it coding? Level Design? Art work? You do not have enough time in your life to master everything.
I for example can develop you a full game full of basic shapes and basic levels because I am not really good at designing characters or models. And it is ok. I ask some designers or buy models when I need some. So I can keep working on things I am good at and do not waste my time.