the process is called UV mapping, which uses UV coordinates (kinda like latitude and longitude) to tell maya what area on the object coincides with the texture you create. in the polygon UVs menu you'll see UV mapping types like planar, cylindrical, spherical, automatic, etc. you use those to create a UV set for your object, which you then lay out or arrange in the UV Texture Editor... you then create a UV snapshot (from the polygons menu in the uv texture editor) and open that up in photoshop, where you paint what colors you want where, and when you bring the newly painted texture into maya, your colors will go where you wanted them to.