Hi Jess, welcome to the site. For starters you might check out the beginner guides and video tutorials on our site here:
Most stuff is in there that beginners want to learn. Just a basic run-down on what you need, are a phone or computer with some free capture software. Clay (obviously) and a few other materials such as wire and epoxy putty for armature making. If your designs require one. You also need a small space to set it up and at least a couple of lights you can use to illuminate your scene.
It can get very complicated the more you delve into it - so if you have any specific problems you need solutions to feel free to ask.