Run through all of the doors to the back room of the level (the power generator will be on your left when entering), gather all of the cubes that are above the ones placed directly on the floor.
Fill in the circuits so each one is a straight line
to keep the door open, but let you pass through while holding some cubes, and then go to where the exit it.
Form another straight line across the roof
to connect the power to the exit, then finish the level.