Vogue knitting relaxed pullover help

Hello,

I’m working on the pattern Vogue Knitting Relaxed pullover. Instructions are telling me: when there are 42 sts, bind off center 12 sts for neck and working both sides at once, bind off from each neck edge 6 sts once, 5 sts once. Bind off rem 3 sts each side.

I have knitted 15 sts one side, binded off 12 sts in center and knitted remaining 12 sts. What does work both sides at once mean? Also, my yarn strand that I knit with is on the wrong end, so do I add a new ball of yarn to work the other side to continue doing the bind off?

Am I doing this right?

Yes, add a second ball of yarn to work the other shoulder. You can either work both shoulders at the same time or you could finish one shoulder and then re-attach the yarn and work the second shoulder.