Sweater Crochet Help

[Butterflycrochet]

Hello

Came across this in my sweater pattern and am confused. 

Rows 55(57,59,61,63)-62(64,66,68,70): Ch 1. 1 Sc in each St across. Turn. Tie off.  ( I finished up to here)

Not sure how to start here:                 Opposite Shoulder:Count 18(20,22,24,26) stitches in on the unfinished side at Row 51(53,55,57,59). Join yarn with a Sl St.

Row 52(54,56,58,60): Ch 1. 1 Sc in each St to end. Turn. (18 Sc)

[Granny Square]

Welcome to the ville!

It sounds like you worked bottom up on the front or back, and then stopped working all the way across at the neck opening to form one shoulder for a few rows - in other words, making 1 shoulder 'strap', and probably  working a straight side at the armhole side and possibly shaping the neck opening on the other side.

So now, you have finished that 1 shoulder/neck shaping and need to make the other side, but the neck opening is wide and you need to skip 18(20, etc) stitches, which is the bottom/low point of the neckline, and attach the yarn where it says, and work toward the other armhole side.

I just remembered I drew a picture to help someone on a similar question a while ago...see below.  Your sweater piece shape may not look exactly like this, but:  you have just finished the yellow shoulder area.  Now you need to skip the stitches which are at the top of the pink area, re-attach the yarn, and work the red shoulder area.  I hope this helps and doesn't confuse you...