Of course, your markers will move up as you knit, but I would put these in Row 2. I would knit into front and back 2 times, k10, and then place a marker; knit into front and back 2 times, k10, and then place another marker . . . all the way across (so, in other words, after every group of stitches that you repeat). Or you could place a marker after every two repeats.
When you come to a marker, stop, and count to the last marker to make sure you haven't missed or added any stitches. It's a lot easier to do this than to count all the stitches at the end of the row (not to mention having to figure out where you goofed and going back and fixing it)!