No, in this case " knit rows 1-12" really means "knit" because you're making a garter stitch border so the afghan won't curl when it's done. Take a look at the finishing instructions. They probably call for the last 12 rows to be all knit, too. The gauge is probably in stockinette to make it easier to measure. Oh...I see it...there's a garter stitch border around the edges, too. The whole thing just looks big, fluffy, soft and inviting.
"Right side" means that from then on, the side you'd usually want to be looking at should be toward you. Stick a safety pin, a little different-colored yarn, a twist tie or whatever onto that side of the afghan so you'll remember which side is "forward". If the afghan is the one I looked up, you'll be working in basketweave, so you'll want to get your knits and purls in the right order.