Need Help with Hat Pattern

Crocheting a hat for Christmas. It's crocheted flat with a seam on the back. I have the piece complete. Now the pattern says "Fasten off leaving a long end. Draw end through rem sts and fasten securely. Sew center back seam."

I don't understand what they mean by "draw end through rem sts". Will this close the hole at the top of the hat some how. This end is 16 sts and about 6 ins. long.

Any help would be greatly appreciated. I've always done hats that are worked in a circle pattern. This is my first worked this way and the pattern instructions have not been the best. Thanks in advance!!