This is my first time knitting and I am working on a scarf. I am using the basic knit stitch and just finished one ball of yarn. I already cast off, but need to make the scarf longer.
How do I add an additional ball of yarn to continue knitting after casting off? Did I make a mistake and possibly have to undo my cast off to add the new ball of yarn and continue knitting? Or is there a way around this so I don’t have to undo it?