/diy/ - Do It Yourself

Blacksmithing noob here, I want to start pic related as a summer project. I have the tools (or at least most of them) to help start (shears/jigsaw, hole punch, hammer), my only questions are what type of metal to use, how thick should the metal be(the pdf I'm using doesnt state how thick the metal should be), and the type of rivets that I need for this.

Any help or advice would be well appreciated.