This is a simple way of making a hollow body. It's not a true hollow body but if you just want to remove some weight and give the guitar a different tone, this is an easy way to do it. Lay the two pieces of the body out (face down) and with a router, hollow out the cavities. Be carefull not to get too close to the sides and do not go any deeper than 1/4" on each pass. You will need to make several passes until you get the cavities as deep as you want them.