Biped's Copy/Paste rollout on the Motion panel provides controls for copying and pasting biped tracks from one part of the biped to another, or from one biped to a different biped. At the top of this rollout are three buttons: Posture, Pose, and Track.

This section covers the copying and pasting of tracks. For information on the other options on this rollout, see Copying and Pasting Postures and Poses.
To copy and paste biped tracks, turn on Tracks. The remaining controls in the rollout change to reflect that you are working with tracks:
The two Paste buttons become Paste Tracks and Paste Tracks Opposite, respectively.
The Paste Horizontal, Paste Vertical, and Paste Rotation buttons in the Paste Options group become active.
For hands-on experience in using Copy and Paste Tracks, see the lesson called Creating a Simple Freeform Animation in the tutorial Animating with Freeform.
To copy a track from one biped to another:
On the Copy/Paste rollout, click Create Collection and rename the new collection Biped Track.
Click Track to use Track mode. Then, select the biped parts whose tracks you want to copy.
Biped creates a new track buffer, and adds it to the list as the active buffer. The buffer's name indicates which biped parts you selected.
Click Paste Track or Paste Track Opposite.
The tracks for all biped parts are applied to the other biped regardless of which parts are selected on the biped.