This pattern has me confused. Specifically this part:
Shape Neck: Next Row (RS): K18(20-22-24-26-28), join another ball of yarn and bind off center 16 sts, k to end. Working both sides at once, bind off 3 sts at each neck edge once, then dec 1 st at each neck edge every RS row 4 times – 11(13-15-17-19-21) sts each side. When armholes measure 7(7 1/2-8-8 1/2-8 1/2-9)”, end on WS.
What do I do w/ the original ball of yarn once I join the new one. Also, what do they mean “working both sides at once”?
Help a newbie.