Ok. You have your hook, your yarn, sissors, everything you need. Let's get started.
First, make a slip knot. Cross the end of the yarn over itself to make a loop. Put the end behind the loop and pull it through, but not all the way. Now tighten it and you have a loop. Put the loop on your hook and tighten it, not too tight though. It should be able to slide on the hook easily.
Decide how you're going to hold your hook. You can hold it like a pencil or whatever's comfortable for you.
Time to learn the first stitch, The Chain Stitch. If you hold the hook in your left hand hold the yarn in your right hand, or the other way around. Weave the yarn inbetween your fingers however its comfortable. Once you figure all that out its time to start crocheting.
Wrap the yarn around the back of the hook and pull it through the loop on your hook. You may need to loosen that slip knot. You have made one Chain Stitch.
Never count the loop on your hook, only the loops behind that one.
Practice the chain stitch and making the slip knot. I'll post How to do Single Crochet next.