I’m just completing my sweater. It has a buttonhole band, and the instructions say to rib 3, caste off 2 stitches, then continue in pattern. Then, on the next row, caste on 2 stitches to correspond with the 2 previously caste off. My question is, how do I caste on in the middle of the knitting? I’m only working with 1 strand instead of 2, which is how I usually caste on when I’m starting a project.Is there a video on this website?