It's based on a "proper" pattern (Sirdar 1771), but with a couple of tweaks.
Step 1: The basic blanket
Cast on 65 loose stitches, then alternate rows of knits and purls (aka "stocking stitch") until the blanket is 61cm (24 inches) long. You can, of course, change the size of the blanket to suit your needs. This blanket is aimed at a newborn babe in her car seat.
It's the next stage that's more interesting.