Here's how I do it...I make the bottom first with appropriate holes... glue it to the bottom of the pan...then I cut a top just a little bit larger....if you need to form it, do it....while it's wet I clip it all the way around with office clips...I let it dry... one clip at a time I take one off and mark each hole through the seat bottom holes so all are marked...I also draw around the bottom to make the exact pattern for the top then cut off excess....then I punch the holes. I know others have different and maybe better ways than me. If I have a photo I'll post it. Good luck