When you retarget animation from one character to another, a new layer containing the retargeted animation is automatically added to the Animation Layer Editor. This layer is named RetargetLayer by default. You can adjust animation on the RetargetLayer, or add additional layers to organize your work. See also What are animation layers?

To key on top of retargeted animation

1. Select > Control Rig > Add to new anim layer to add the Control rig of the target character to a new animation layer.
   NoteTo add the Control rig to an existing animation layer (such as RetargetLayer), select the layer in the Animation Layer Editor, then select Control Rig > Add to animLayer: <layerName> in the Character Controls.
2. Select a point in time where you want to change the position of the target character, then use the Control rig effectors to adjust the position of the character.

   Ensure that the Reach values of any effector you want to adjust are set to 1. Otherwise, moving or rotating the effector will have no effect. Reach is set to 1 by default for the ankle effectors.

3. With the animation layer you want selected, set keyframes where you want the position adjusted.
4. Repeat these steps until you are satisfied with the adjusted animation on the Control rig.
5. Playback your animation.

   The target character animation is now modified, and all of its animation is contained on the selected animation layer. You can create more layers to organize your adjustments, or continue using the single layer. When you finish making adjustments, you can merge animation layers together, or bake the animation to the target character.