What materials can I use to build this (for practice mostly, as I have never built a thing in my life)? Will cardboard work or should I try to get something else?
Welcome to the 405th! The files here are primarily designed for the pepakura (AKA papercraft) method, which involves printing the pattern pieces out (paper works but cardstock is better), cutting them out and then sticking them together to form a 3D model, like a net shape. This is typically followed by coating the pieces in resin, body filler and/or fiberglass to smooth it out and give it strength.
If you have access to the Pepakura program, you can simplify these unfolds to work better for EVA foam or cardboard. The program is free to use for the most part, however you will need a key to save the file.