Pattern Help

Hello, I have started knitting recently - mainly for my niece as my sister loves baby knits! I’m currently knitting a simple wrap cardigan and am struggling to understand some of the phrases used. Just wondering if you could help at all!

The phrase is talking about the back section, and says cast off. Rejoin the yarn to the other side of the neck and purl 18sts, turn. Cont in stst for 1.25cm then cast off. Does this mean I need to sew the yarn to the other side? How do I rejoin it?

Many thanks!!

Hi Lizzie, welcome to KH!

Can you post a pattern name and link if possible? It makes it easier to help.

It’s from a knitting magazine. The magazine is 50 baby knits spring 2015. Attaching a photo of the pattern,

Welcome to the forum!
Just start knitting with the new strand leaving about a 6 inch tail. The first few sts may be a little loose but keep knitting. You can always snug up those sts later. When you’re finished with the neck you can weave in the end.