Here are the directions for the next part:
Shape Shoulder and Back Neck Bind off 7 sts at beg of next row, work 12, sts, join 2nd ball of yarn and bind off center 29, sts, work to end.
Next row (WS) Bind off 7, sts at beg of row, work to end. Working both sides at same time, bind off 6, sts at beg of next 4, rows. (the rest doesn’t apply to your size)
Begin by binding off 7 at the beginning of the RS row, knit across 12 stitches. Now leave the yarn you have been using and use another ball of yarn if possible, or the other end of the skein if you must). Beginning with the new yarn knit 2 stitches and bind off the first one keep binding off until you have bound off 29 sts in all. Then go on and knit across the rest of the row (I believe you will have 19 stitches past the bind off altogether).
Turn to work in the other direction. Now you are on a WS row. Bind off the first 7 stitches and purl across the rest of the sts (12). Leave that yarn there and pick up the yarn on the other side of the gap you made when you bound off 29. Purl to the end of that row. Turn and and on the RS bind off 6 stitches. Knit to the gap, leave that yarn. Pick up the yarn on the other side and knit to the end of that row. Turn.
Bind off 6 in purl at the beginning of this row. Purl to gap. Leave the yarn. Pick up the other yarn and purl to the end. Turn. Bind off 6 (all the stitches on that side are bound off now). Knit the stitches on the other side of the gap with the yarn for them. Turn. Bind of the remaining 6 stitches in purl. Now the shoulders are done and you have a dip in the middle of the back for the neck.
You want to do the bind offs at the beginning of armhole side rows so that the shoulders will slant the proper way.
For a more nicely shaped shoulder, without the stair step affect you get by doing it exactly as they say, you can make this change. Just at the end of each row where you are going to turn and bind off 6 (don’t do it on the first ones on each side with the 7sts), instead of working all the stitches, work to the last stitch and slip it. Turn, work that slipped stitch together with the first of the stitches as you begin the bind offs (k2tog, or p2tog depending if you are on a RS or WS row). Since you worked 2 together, only bind off 5 after that. You will have gotten rid of 6 as it says but you will have a more gentle slant on the shoulder. It will be easier to sew up. This last paragraph is optional if it confuses you, just do it exactly as given above.