Blender Character Animation Book....

Ok so ive gone through the chapters on Rigging the character with bones.

From my understanding you have the body bones and control bones that help the KI and the FL operate with out having to go in an manually move ever body part right?

The reason im asking is because i followed their orders step by step and my upper body rig mover around like it lost its center of gravity and the bones jumped sparaticly everywhere.