How do I add the contrasting color when double knitting? The instructions I have say with a slip stitch, but I do not know where the stitches then materialize from. What is a slip stitch and how do I get to the point of having the colors alternating on the needle? I already have my 84 main color stitches done and I understand knit 1 purl 1, but do I have the contrasting color stitches on a third needle or somehow create them as I go?
When I made a double knit scarf, I cast on both colors at the same time.
Amy has a double-knitting video on this page (scroll down a bit). Maybe that will help.