How Limber Works
If you've never used a rigging tool like Limber before, try this: Make a new comp and click the
New button, followed by the OK button. You'll then see three layers added to your timeline and one of them will be selected. Drag this layer around and feel how intuitive it is - that's the power of IK.
Every new limb has three layers like this: the limb layer that renders, and two controllers that are guide layers - the start and end point of the limb. As you move the controllers, the limb layer responds.
For a simple character, you could parent the start controller (it's probably called left-Hip) to a body layer, and parent a foot or hand layer to the end controller or better still, a locator. Limb layers are better off left un-parented.
With the end controller selected, if you look at your Effect Controls panel, you'll see that it has an Effect called Limber that contains properties to change the limb's length, switch from IK to FK, and so on. Every single limb has it's own copy of this effect and you will use it to set or animate the property values per limb. If a limb has styling properties like colors and sizes, those controls are in a separate effect, on the limb layer.
Properties are grouped, so you'll need to twirl down a group to see the properties inside it.
