Dorsal fin

Would anyone be kind enough to check the following paragraph for me? Thanks a lot.

I like Do-It-Yourself Puppetry classes the most. All the classmates of EGRC were assigned to make a cute puppet figure by using the materials they were provided with. First, we used a Styrofoam ball to make the puppet head by pulling the sock over it. Next, we cut a piece of the non-woven cloth in the shape of its frame based on which you can design. Then, I designed a cute green crocodile with yellow dorsal fin and white teeth as a decoration on the costume. Finally, everybody presented his own work and put them together on a desk, and we took a picture with all the special puppets. I had fun at this DIY puppetry class.