I am brand new to knitting and trying to figure out how to use my long looms. I have a few books, but am a little confused about casting on. In one book, under "Cast On" it shows how to cast on to the loom and use a scrap piece of yarn over what you've wrapped. I want to use a zigzag stitch to make a scarf, but it is different from the casting on stitch. Can I cast on with a zigzag stitch? Is the piece of scrap yarn necessary? I probably shouldn't be this confused...