The chain stitch is usually used to start a flat piece. It’s also often used to start an oval piece, increase the height of a new row, and create embellishments.
Here’s a chain with 13 stitches in it. I’ve called out the second chain from the hook, because if you’re making the next row with single crochet stitches, the first stitch you make will be in the second chain from the hook. This is because the chain that you skipped gives this first single crochet stitch its height.
To help keep your chain straight, and make it easier to create chain stitches, keep moving your yarn-holding hand as close as possible to the base of the upcoming stitch.