Baby boy 5 hour sweater - confused

I started making this and have just finished making the sleeve. I don’t understand what is meant by this:

“Bind off leaving last stitch on needle. With right sides together slip stitch sleeve closed being careful to close up all the holes at the underarm. Place last stitch on left hand needle. Knit 2 tog and knit across to next marker.”

This instruction isn’t in all the versions online. to me it means - leave one stitch on the needle when I bind off and which I then bring it back up to the top and knit it into the back. I know that’s not what its meant as that would mean the cuff was stuck to the back - so what does it mean? Crochet it closed or something?

Tempted just to bind it all off and sew up sleeves using mattress stitch and ignore it…

I think they want you to crochet the sleeve seam closed and when you have one stitch left from that, you’ll attach that to the rest of the sweater.

ahhh, well I’ve had enough mix-ups already in the difference between British and American knitting abbreviations - I cast off (bind off) 2 stitches when it meant to cast on 2 - and I was wondering where 4 stitches had got to - I think seeing as I made the sleeves 2 different colours I’ll stick to my alternative plan! Otherwise I’ll have a pink seam running through a white part…

I just finished this sweater, and I did exactly what you suggested! I didn’t like the idea of a crocheted seam, which is what I thought the pattern might be suggesting to do, although it was a little confusing in that area.

yep I workied it out in the end but went with my original plan, I used some left over wool though so it looked a bit too girly when finished, so I crocheted on a blue trim and added button holes while I was at it - I’m not too good at crochet though!