BUILDING A GAME BOARD

I look at this Miggle game I have and there is nothing to it, metal, and a motor on the underside! Is it just as easy for custom games? Even if one uses a wooden frame, can't you just screw light metal (the field) into the frame, attach the motor?

The field sheets that I see, are they just a magnet sheet on top of the sheet metal?

If someone could, please explain how to build a game in a few short sentences???