To begin, you'll need to make the first loop on your hook, a slip knot.
Pull the yarn strand from the center of the ball. Make a loop shape 5" or 6" from the end (the tail) by placing the tail in front of the ball yarn, then letting the rest of the tail yarn fall slightly behind the loop.
Insert your hook into the loop. Scoop up the yarn in the back of the loop with the hook. Pull through the front of the loop. Gently pull the tail yarn to tighten loop around the hook. In crocheting, the slip knot does not count as a stitch.