Once you have all of your string cut, tie a knot at the very top of the strings. Then, divide the string into 3 groups (they won't be even groups, but it doesn't matter), and braid them together. When your braid is about 1.5-2 inches long, tie a knot at the bottom. Having the ends of your bracelet braided will make tying it on much easier.
This is an easy step. Spread out your string in this pattern: 1, 2, 3, 4, 4, 3, 2, 1.
Step 5: The Knot
Here's where things get a little tricky, but I'll try my best to explain, and maybe the video will help.
Take String 1 (remember 1, 2, 3, 4, 4, 3, 2, 1) on the left in your left hand, and String 2 in your right. Take String 1 and lay it across String 2, so it makes a right triangle pointing towards the left. Then, still holding String 2 in your right hand, take your left hand through the middle of the triangle and grab on to the end of String 1. Pull String 1 under String 2 and through the triangle, and then pull it tightly until your knot slides to the top of the bracelet. Do this twice with String 1 and 2.
When your bracelet is the length you want, tie a normal knot below the last row, just like you did in the beginning. Then, separate the strings into 3 groups and braid them together. When your braid is 1.5-2 inches long, tie another knot. Cut off the excess string just below the knot.