Can anyone clear up what the line "join in yarn MC" means in the following instructions for me? This is at the very beginning of a pattern for a dress:
"Using size 8 needles and waste yarn, cast on 14 sts. Beg with a K row, work in St st for 4 rows, ending with RS facing for next row. Break off waste yarn and join in yarn MC."
This is the first time I've used an invisible cast-on, and I was able to do that just fine. But what does it mean to join in the main colour yarn, though?? And how? Help!