Haha! It's pretty simple, but tricky to explain, but I'll try!
1.) Use the trianges to make a cube outline, aka the red green and blue. (don't color inside yet)
2.) Copy the outline, and move it to where you want so there are more than one cube. You have to start in the back, then move forward with the cubes to the front.
3.) After you set the outline, color it in with magenta, yellow, and cyan.