Biped essential 5 keys for animation

3 keys for Center of Mass
Rewind the timeline to frame 0.

Click anywhere on the biped, and go to the motion tab.
The procedure is, click the arrow button first, then the red key once.

First is setting a Horizontal key

 Key 1

Second, set a Vertical key

 Key 2

Then, set a Turning (Rotation) key

 Key 3

Next are 2 keys, one for each foot. These keys will make the feet stay on the floor when the biped crouches down. This is part of what is known as IK or Inverse Kinematics.

Select one foot, and hit the planted key button.

And now for the last key: select the other foot, and hit the planted key button. Done!

 Key 4  Key 5