previous post, ch 1 (or make one chain stitch), and turn the piece.
Yarn over again and pull the yarn through both loops on the hook. You have now made the first sc of row two.
Now sc in the remaining stitches of the previous row. Congratulations, you have made 2 rows! What you have just done would normally be written like this: ch 1, turn, sc in 1st sc and remaining sc across.
You can now add as many rows as you want by repeating the instructions for row 2.