Step 1: Choose components wisely
The actions I planned for the buttons is to trigger some lights and one motor. I have chosen leds for almost all of them except for two, because I wanted the box to work with batteries. I used four C type batteries, so the box works a while with this power source.
Step 2: Mesure all components
The holes I needed to place the parts do not needed to be so precise, so I used a compass and a ruler. Otherwise I would have been purchased caliper.