I know it's not written like that, I was just laying it out for you row by row.
Following means 'after'; the clue to knit a plain row with no decs is in the words 'following 2 alt rows'. Which translates into - after this, work the decs every other row 2 times. So you do a dec row, then a plain row, a dec row, then a plain row.
sue- knitting heretic