This pattern calls for the use of... Granny Squares! I didn't know how to make them before, but now I do, thanks to this pattern. They're a lot of fun, and can be used to make lots of different things. Many patterns call for a bunch of granny squares sewn together. Here's a picture of my granny square:
Making a granny square requires these stitches - a slip stitch, a double crochet stitch, and a single crochet stitch. All of them are basic and easy to learn. The double crochet is my personal favorite, just because it's "complex", but not really - it's easy, and it creates a bigger stitch, which is satisfying. Crocheting overall is really easy - you don't need much to get started!
My granny squares - I haven't trimmed them yet.