Next, you're going to repeat the same exact steps again in the next chain stitch:
Photo 17 shows my crochet hook pointing to the spot where I'm going to insert my hook to draw up the next loop. Photo 18 shows my hook inserted into the back of the chain stitch. Photo 19 shows me grabbing the yarn with the hook. Then I pull the yarn up through the chain stitch; photo 20 shows how it looks after I've drawn up the loop.
You're going to repeat this sequence all the way across your starting chain, pulling up a loop in every chain stitch until you reach the end of it.