get some wood and a saw, that should be a good start......

?
Just kidding.
What I did with my old seats was take them apart peice by peice and copy the cuts and start by using wood glue to keep them together. The when finished you can either glass them or screw them together. I kow that there are alot of other opinions out there but thats what worked for me. If you don't have the old seats good luck.....