Pattern Help

I need to know if I do this whole sentence 3 times, or do I just do the the 2 BO rows and then the dec row 3 times:
Working with 52 sts.
Armhole shaping: Working back and forth in rib, bind off 2 sts at beg of next 2 rows, then dec 1 st each end every other row 3 times - 42 sts remain.

Or do I do a BO row a dec row a BO row (3 times). I am making the Brittany Jumper #130 by Minnowknits.


No BO at the beg of the next 2 rows, these will be the RS then the WS rows. Then the next row is a RS row and dec at the beg and end of the row, work the WS row with no decs, dec on the RS row, work the WS row, then the RS row with decs.