After the slip stitch is made, you'll need to cast on. This means adding more loops onto your needle to be knitted. The number of stitches will determine how wide the piece will be. I'm demonstrating here the Long Tail Cast On method. It gives you a more flexible edge when knitting. It seems very complicated when you first learn this, but I find it fun and relaxing. The main thing to remember is that your "tail" will be used to make the stitches, so allow about three times the length that you want the finished piece to be. I find this to be the hardest part. I'm forever having to start over because I didn't allow enough yarn, then when I undo the cast on and start over, I end up with too much yarn. It's an ongoing learning process for me.