Creating Mips Help

[SUPEREEVEEMASTER]

I'm in the process of creating tracks using Sandbox and I'm curious into how to make your own mips instead of just copy and paste from tracks that you have downloaded. For example I want to make a wall like the one you see below and change the red to blue.

Does anyone have any idea of how to make or change mips? If so, can you make sort of a step by step guide. Any help would be nice.

 

[MattyO]

Come on man. Search the forums.