Ignore the "n k5. *P1. K5 n" part. I copied that to see where I was in the pattern as I replied and forgot to erase it.
It's not as hard as you're thinking, you need to keep to the broken rib pattern, which means you k the stitches that were knit on the k5, p1 row previously, and purl that 1 stitch. The edge sts will be hidden in the seam so you can ignore them and just do them as knits on RS, purl on WS. Then inc between the edge st and the next st and do the stitch after that in the pattern.
You're expanding the k5 p1 pattern from the center out; since it begins and ends with a k5, the first row after the inc will put a p1 before and after the center sts as well as another inc. Then the next row will add a k1 before and after, the one after that will have 2 knits and a purl before and after, etc.
sue- knitting heretic