Cast on stitches to existing project

How do you cast on stitches to a project that has already been fastened off?

Can you link to this pattern? It does sound unusual.
You can [I]pick up[/I] sts on a project that has been bound off or fastened off.

Thanks for your reply.
My pattern is in a book of doll clothes. It says, work 1st step & fasten off, I did this, then it says cast on 13 sts. leaving 1st 3 ridges unworked for armhole, beg in next ridge to pick up & knit 14 sts. I am so lost!

Fasten off isn’t the same as cast off though. But cast on 13 with a new strand of yarn, then pick up sts around the armhole. There’s a video on the Tips page for picking up sts. It shows it on a bound off edge, but you can do it along an edge that’s at the end of a row.

OK, it sounds like this is worked in garter stitch. What if you cast on 13sts with a new end of yarn, then pick up and knit 14sts along the garter ridges? Start picking up the 14sts after the first 3 ridges of garter st. See if that makes sense with the picture.

Yes, part of that makes sense to me, & I’ll bet you’re right. But, I’m not that experienced & I don’t know how to cast onto a piece that has already been fastened off. It is worked in garter stitch. I do know how to pick up sts.

I would do the cast on with a new end of yarn just as if you’re casting on for the beginning of a project.

Thanks, I can do that. Thanks so much for your help.