Step 2: First lamination
Lay out the materials by taping together a sheet of balsa strips the approximate size of the skateboard mold, maybe a little bigger. On this, place your fiberglass cloth, about the same size. Two layers would be fine.
Mix up some epoxy, probably not more than a few ounces, and work it into the fiberglass until it is all saturated. Then place the balsa sheet on the mold, fiberglass side up, and put the 1/2 foam sheet on top of that. Tape them in place on the mold with a couple of strips of masking tape, then wrap the whole thing with release film, stick it in the vacuum bag, and suck all the air out. You can see how all the layers press together and form to the shape of the mold.
Once it was under vacuum, I placed the mold over a couple of pieces of wood with a heavy weight on the center to create some "camber" in the deck. This isn't necessary for a good board, but I wanted as much resistance to my bulk as possible.