Can anyone tell me how you can add (step by step) a new gui and buttons and stuff? Also can anyone tell me if it is possible for me to move some the element sections (GAS, SOLID, etc...) to the left side so it won't be crowded?
You don't need to use the Model/View/Controller thing that all the other guis there use. It might take a bit of understanding in the source to make it work though.
Also moving the menus to the left side of the game would be extremely hard, the graphics and other things in the game always assume that the simulation is in the top left corner and everything is on the right/bottom edges.