You could make a tri--lam with a hickory back, bubinga core and for the belly personally I'd look for a place that sold ipe deck boards.
However my advice would be to forget a laminated bow for now. Find the best maple or hickory board you can eg. the straightest possible grain. Try digging your thumb nail into a piece. Soft maple will dent easily. If not it is hard maple.
Unless you can't find a straight grained board you do not need to back your board.
As for design you cannot beat a pyramid for your first bow. Most designs actually shoot within 10fps of each other if executed well
So don't get hung up on some fancy design. Pyramids shoot very well and are easy for a beginners eyes to tiller.
Make it 68 long.
Widest part for maple and hickory 1 3/4" wide with a taper to 1/2" wide tips.
Rough out your thickness at 5/8ths for most of the limb, bit thicker at the handle.
Get a board at least 3/4 thick, 1 inch better as a minimum. This thickness will allow you to simply glue an 'extra' piece on for the handle without risk of delamination which can easily happen with a board that is too thin to start with.
Good luck