One day I will learn to Double Crochet, maybe even Triple Crochet (if that is a thing). For now all I can do is single crochet, and this is how I do it.
In this little crochet circle you can see the stitches running in a chain around the edge of the work. When you are making a single crochet you need to put the hook through both strands of wool in the stitch (this is something I got wrong at first because in knitting you would only put the needle through 1 strand.
Step 1: Crochet Hook
Put the crochet hook under the two strands that form the stitch.
Step 2: The Wool
Wrap the wool around the end of the crochet hook.
Step 3: Pull Through
Pull the wool through the stitch. Now you have two loops on your crochet needle.
Step 4: Finish
Wrap the wool around the end of the crochet hook again.
Pull the wool through both of the loops on the hook.
Tighten gently to finish.