To start, make a slip knot at the start of your yarn.
YO (yarn over) - now, this is the funny part...I have been told that I do this backwards and the yarn should come from the front to the back, I do it that way for the chain, but for actual stitches, I yarn from back to front.I have never had any trouble with how I do it...so, my suggestion once again is to do it how you are comfortable.
Now, pull the yarn through the loop.
Woo Hoo!!! You just started your chain. Now, for good practice, chain a long strand just to try and get each stitch even.
This picture is the top of the chain. It's just a braid, but important to understand that this is what it looks like. There are 2 strands of yarn on top. These are considered Front Loop (frond lp) and Back Loop (back lp). Some patterns call for stitches to be made in a single strand of yarn instead of both. When this is done on an afghan, it gives it more texture to sight and touch. (I will go over this at a later time)
To be honest, I don't mind crocheting chains, but my least favorite part is the first row of anything when you have to crochet in the chain. Once I get past that, it's all a breeze.