Take a deep breath, you'll get it.
You've probably read or heard that ribbing is knitting the knit stitches and purling the purl stitches. So when you get to the second round if you started with a knit stitch in the first round you will start the second round with a knit stitch. You just follow what you did on your previous row.
The only time this won't work is if you have cast on the incorrect number for the type of ribbing you want to do.
k1p1 is a multiple of 2 - so any even number will work
k2p2 is a multiple of 4 - so the number needs to be evenly divisible by 4. Like 76, 80, 84, 88.
Here's a sample of what the stitches look like.