Neck shaping instructions help

I’m working on a sleeveless cable sweater, and am almost done with the back piece, and I’m stumped on the last bit of instructions.

So I’ve got 20 some odd inches of knitting done. And 60 stitches on my needles. These are the instructions for the Neck and Shoulder Shaping:

Bind off 2 sts from each shoulder edge 3 times, AT SAME TIME, bind off center 38 sts and working both sides at once, bind off 5 sts from each neck edge once.

[b]Basically – I understand each chunk on its own, but I don’t get how to do it all at once.

Won’t I need to join an extra ball of yarn to one side of the neck so that I can do the two halves at once?[/b]

The instructions for shaping the neck / shoulders for the front piece make more sense:

work 16 sts, join 2nd ball of yarn and bind off center 28 sts, work to end. Working both sides at once, bind off 2 sts each neck edge 5 times. When same length as back, bind off 2 sts from each shoulder edge 3 times.

Yes, you will need extra source of yarn to do both at once. I’m sure someone else with more info than me will be chiming in anytime here!

Good luck!