The first loop on the hook in crochet is created by a slip knot.
1 Make a loop of the yarn around your fingers.
2 Pull a second loop of yarn through the first loop.
3 Pull up the loop, but do not pull the end of yarn through.
4 Slip the hook through the second loop and pull the loop taut around the hook. Do not pull too tightly or the first chain will be hard to make.