I started by glueing together foam blocks. Then I printed out the profile of the body and cut it out. I glued that on to the side of the foam to use as my template.
I sanded the foam down to the desired template profile.
I laid the fiberglass resin material on top of the foam. I let that stand for about 24 hours until dry.
This is how it looks after I remove the foam from the inside of the body. I don't like it. It contains a lot of air pockets, bulges and rough spots. For my first time working with fiberglass, it isn't too bad, but not as good as I would like it.
Here you can see my first attempt at making the body. In the background is my 2nd attempt. The 2nd attempt already looks more promising than the first.