Hi Lizzie,
Yes, you would add the sts at the end of the ribbing. (edit: on the first row of stockinette)
The pattern is using a self-patterning type of yarn, and the writer is trying to explain how to match up the self-striping/patterning behavior to have the pieces look the same.
Yes, of course you'd want the 2 sleeves to be the same length...and you can accomplish this by doing both at the same time or keeping track of the # of rows you do before starting armhole decreases.
HTH
Diane
