Surfing Waves

I'm planning on building a Bellyboard.
There doesn't seem to be any sources online that tells you how to so I got a few questions.
Should I put any rocker on it?
What is the best type of wood to make it?
What should be the length and width if I'm 5'7 and weigh 100 pounds?

I have made a few wooden paipo boards. I used marine plywood which is made so it doesn't fall apart with exposure to water. Probably other wood or regular plywood will work if it's sealed. I put a nose rocker by placing the board on a table with the nose hanging off , then placing a heavy weight on the body of the board to keep it from flipping when I place a lighter weight on the nose causing it to bend. Then I poured boiling hot water on the nose and waited a day then took the weights off. I also shaped a concave in the nose narrowing midboard and widening at the tail. I also fiberglassed the bottom of the board and glassed in a fiberglass rope in the nose to hang on to it. I made the rails turn up and the shape like a parabola. Pointed at the nose and the widest part in the back. I am not sure the size but my preference is at least from my crotch to my chin which is about 3 feet on me but I used a 4 foot paipo board with a nose rocker. Perhaps on your first one just do an outline and rails and paint it or resin it to seal it. See how you like it then make another if you enjoy it

What did you use to seal it?

I used resin