You're almost done! Now all you have to do is slide the loop that's on the right-hand needle onto the left-hand needle, above the slip knot loop.
Now you have two stitches. This isn't the way you finish a knit stitch, but all the other steps are the same, so once you get your cast on finished, you'll be ready to roll with the knit stitch.
To cast on the desired number of stitches, just keep repeating these steps until you have the required number of stitches on your needle.
The other really simple way of casting on is called the long-tail cast on; we'll cover that next.