Toy monkey in progress

So as my second project, im knitting my daughter a monkey. I have knitted everything except for the limbs. I have finished the first arm and am working on the hand. This is an Alan Dart patter from Irresistible gifts to knit vol 2. after the middle fingers it says ‘draw up tightly and fasten off, then join finger seam’. so far all i’ve done is break yarn and thread it through the sts on the needle and pulled it tight. I am unsure how to ‘fastnen off and join the finger seam’. Thanks in advance for the help!

Fasten off by pulling the sts smugly and threading the yarn back through a couple of the sts. I tie a single knot through one of the sts at this point so that the finger doesn’t open up at the end. If the finger was knit flat then the seam would be down the side of the finger. If you’ve left enough yarn after closing off the end of the finger, you can use it to close up the seam.