Freecad for 3d concept

[iamd]

Hello, people hope everything is going well for you. I take the past week to learn freecad. I was trying to model something for a 3d concept i am working on but at this point, it became unmanageable because of the slowness and I have no Idea about what is happening. I Just model a tiny part of the personal project so I can't imagine how hard it will be later on. I attached the freecad file maybe I made a mistake if you can help me on that.

https://goo.gl/S0PIDc