The single crochet stitch is the most fundamental of all stitches in crocheting.
Please pay attention, that if you are crocheting rows, you will never work in the first chain from the crochet hook, unless the pattern you are working specifically directs you to do so.
After you form the foundation chain of stitches, insert the hook through the 2nd chain from the hook. Bring the yarn over the hook from back to front, hook the yarn and draw yarn through the chain. You now have two loops on the hook. Wrap the yarn around your crochet hook again and draw the hook and the yarn through both loops on the crochet hook. One single crochet stitsch is now complete.
Insert the hook in the next chain as before and make the second single crochet stitch.
Here you can watch a video on how to make single crochet stitches (click on the link):https://youtu.be/0-jnqGRldNs