Hello again, and apologies for yet another question
Following the great advice above, I've finished knitting the hat. I did the decreases as mentioned, and I've now ended up with 20 live stitches and a piece that looks like this:
I'm assuming that the live yarns are the crown of the hat, and the two edges need to be seamed together to finish the piece.
To finish, the last instruction is:
Cut yarn, leaving a 10" (25 cm) tail. Pull through remaining sts and secure.
I'm not entirely sure what to do? I've only ever done simple knitting projects, most of which end up with traditional casting off. I don't think I'm meant to do that with this hat.
Thank you Very Much for any advice