I will show you how to tie a figure 8 knot and a figure 8 follow through.
Step 1: Starting the knot
This is a simple knot, so just follow the pictures.
Step 2: Finishing the knot
Cross the string under, and then push it through the hole. Pull tightly, unless you are going to do the follow through, and leave it somewhat loose.
Step 3: The follow through knot
The follow through knot should be tied around something, brought back, and followed through the path of the 8 knot. Look at the pictures. Basically follow through the 8 knot backwards.