It means that as you do each row of the body, you do the next row of the cable patterns, as you've already established them -- so on Row 6 of the Body, you're doing Row 2 of the cable pattern, on Row 7 of the Body, you do Row 3 of the cable pattern, and so on.
Basically, there's the pattern for the Body, and the pattern for the cables, and they're two different things that are happening at the same time.
I know it seems complicated when they write patterns out like this, but it actually saves a lot of time, space, and confusing writing! Honest, it'll become second nature eventually and you'll wonder why you thought it was confusing at first!
ETA: I agree it's a confusingly written pattern, tho. I agree with Marria about the stockinette stitch, at least on first glance!