Can you look at the picture of the sweater and tell if it continues in pattern on the upper portion of the front?
Despite the fact that it doesn't tell you to continue the 11 rows in pattern, I'm guessing that that's what you should do. That means that every other row you'll decrease one st at the armhole edge. The next decrease will be on a row 1 and it will interrupt the pattern. That's ok but because the pattern repeat has 2 increases (the yrn's) and 2 decreases (the p3tog) I think you should switch to all knit st for this first pattern repeat and then continue the pattern with the next repeat. Eventually, all these knit sts which are replacing the first repeat will be decreased anyway.