The pattern doesn't say anything about adding stitches, but it does say in bold letters that it is imperative to slip the first stitch of each row to work a single crochet later on. It actually says this as a reminder several times all throughout the pattern.
This row I'm on is (knit 2 together, knit 1) 5 times, knit 2, (knit 1, knit 2 together) 5 times.
The next 8 rows that follow are 2 x 2 ribbing.
Just glancing through the rest of the pattern I don't see anywhere else that it shows to start off a row with knitting 2 together.