I think it means that you continue in stockinette stitch with a knit row--and when they say the next and following 6th rows, them mean your increases are starting with the the next 6th row.
So you start your increases on the 7th row, 13th, 19th, etc., until you are up to 64 stitches.
The reason I think you wait until the 7th row is that increases are not usually started at the cuff--at least not that I've ever seen.
You can either just kfb in the first and last stitch or k1, m1. It's up to you. The seaming will hide the kfb increases.
Edited for clarity.