It's really simple, I promise! First you pick out the square pillow you want to use, I suspect you could use oval or round, but the sides will be bunchier, than with the square shape. Then you pick out the fabric you want to cover it with. Pretty simple so far, right? Right!
This is where I had to do it a bit differently than the tutorial. She recommends using a piece of fabric that's two twice as tall, and three times s long. Doing so ended up being too short for me. I did it with two and a half as tall, three and a half as long, and it worked but barely. Next one I do I'll make it's four times as long. You can always trim the excess t the end if you want, but I think it'll be easier with more fabric to work with.