join yarn, nothing to join to

I’m working on mittens from freevintageknitting.com (A B C Children’s Mittens Pattern #156). After finishing the thumb (break yarn & sew up thumb), it says, “Place the sts off first st holder onto a needle; tie yarn in, with the same needle pick up and knit 6 sts on the thumb gusset”. How do I “tie yarn in”? There’s nothing to tie it to!

What am I supposed to do?

You can just hold the yarn end with the right hand, along side the right needle as you pick up the 6sts in the thumb gusset. Leave about a 6 inch tail so that you can weave the tail in later. The first stitch or two may be loose but you can always give a little tug to the yarn end to tighten up.
http://freevintageknitting.com/knitting-mitten-instructions/doreen101/abc-childrens-mittens

Thanks for the link!! I’ll try that & use the tail 2 close any gaps