The Pose tool is used to pose characters by manipulating objects. This is similar to the Objects tool except that it treats bones as a special for superior interaction.
Select the objects to manipulate, and right-click to complete the operation. You will be presented with one or more Pose handles for bones and Object-specific handles for the other object types. Each separate bone chain will be given its own Pose handle. Bone chains that branch will have a separate Pose handle for each branch. Any bones that are controlled by an Inverse Kinematics solver will have a Pose handle attached to all the bones in that chain (even if not all of the bones were selected). These handles let you manipulate the bones in a variety of ways, depending on the type of solver applied to the bone chain. To transform more than one object at a time, change the Handle mode menu in the Viewer Controls toolbar to Global Transform. This is also available via the Ctrl+Right mouse menu.
For bone chains with an Inverse Kinematics solver, you can move the end affector and you can apply a twist. The twist will move the twist affector if there is one; otherwise, it will modify the Twist parameter of the solver.
For bone chains with Forward Kinematics or no kinematics, you can select any bone in the chain and manipulate it directly. You can also select the transform handle at the end of any joint, and manipulate the handle. Doing so will use inverse kinematics to assign new rotations to every bone higher up the chain. The transform handle is treated as if it were an end affector for the chain. For chains using Forward Kinematics, the bones are manipulated by transforming the end affector for each bone. For chains with no kinematics, the bones are manipulated by changing the Rotate parameter of the Bone objects.
Any joint in the chain can also be locked by shift-left clicking on the transform handle at that joint. Locked joints appear with their transform handles solid shaded. Unlocked joints appear with their transform handles in wireframe. When a joint is locked, modifications made higher up the bone chain are not allowed to affect the position of the locked joint.
If Secure Selection is turned off, you can select any group of objects in the viewport. Pose handles will immediately appear for this new set of objects. You can also select bones in a network editor, and the handles will appear for this new selection.
WHAT TO DO NEXT
When posing the character, see if any capture weights need tweaking. If so, experiment with editing capture regions (the procedural approach) or with Paint/Edit Capture Weights. Mirror Capture Weights will come in handy if you have painted or hand-edited the weights of one limb and want them reflected automatically to save time.