Choose the signature at the bottom of the pile, the one that will be the last signature in the book. Replace the tape on it, pressing the tape down flat on the left side (the back of it) and leaving it loose on the right side (the front).Calculate how much thread you will need. The thread will run down the length of each signature between the two outer holes, so multiply that length by the number of signatures you have made, and add a few extra inches. For seven signatures, I pulled out my wingspan's length in thread and it was just right.Tie a knot in the end, and start by inserting the needle into the lowest hole. It will be difficult to pull through the first few times since the thread at the eye of the needle isn't compressed yet. Wiggle the needle back and forth and you wont have to pull as hard. Insert the needle up through the second hole, pull it over the tape and put it into the next hole, weaving it back and forth.Once you reach the last hole, pull the thread gently to tighten. DO NOT pull it straight out from the hole, pull it along the spine, so it doesn't put stress on the holes in the paper. (Shown in one of the pictures)To add the next signature, lift up the loose ends of the tape and place the second signature on top of the first, securing the tape over it. insert the needle into the top hole of the next signature, and continue sewing down the spine.