Figure- are a great knot to use when you need to make a loop or bight at the end of a rope that won't slip. I mainly use a figure-eight knot when I am being tethered in with a harness or making a loop at the end of a rope. There are different ways to tie into a harness, but the main thing is to use a knot that wont come undone and will hold. The following are instruction when tying a figure-eight on a bite.
Step one - Take the end of the rope and create a bight by folding the rope over itself with approximately two-feet of the rope.
Step two - While holding the bight in one hand, create a loop in this standing part with the other hand, similar to the way you made your loop in your bowline knot, thumb down, twist your wrist. The further down the rope you go, the larger bight you have at the end. So don't go down too far.
Step three - Twist that loop one more time by changing the position of your fingers that are holding the loop and twist.
Step four - Place the bight, or running end through the loop and tighten.