Binding off ribbed stitch on knitting board

I work on a knitting loom, knifty knitter, a provocraft item. I have completed 1 panel and want to bind off with a mattress finish. I know to sew through the last stitch, twice. Then to go to the next stitch and sew through twice. Is it the stitch directly to the right of the first one, or the one directly above the first? HELP!!!