Work with the hand in Auto IK mode and by directly rotating it until it looks something like the earlier illustration. Now, take a look at the Action Editor. It has several rows, or channels, and each has a name that corresponds to a bone in the active armature. When you select a bone in the 3D view, the corresponding channel in the Action Editor is selected. Just the same, RMB clicking a channel name in the Action Editor selects that bone in the 3D view. In the illustration, the lower_arm.l cha