You can set keyframes with TCB interpolation, or you can change keyframes to use TCB interpolation.

To set keyframes with TCB interpolation:

1. In the Key Controls window, select TCB from the Type menu.
   

   Key Controls A. TCB interpolation type selected

2. Set keyframes (see Setting keyframes). The keyframes you set have TCB interpolation until you select a different type of interpolation.

To change the interpolation of a keyframe to TCB:

1. In the FCurves window, select the keyframe or keyframes whose interpolation you want to change.
2. In the Tangent options, select TCB to set the interpolation type.
   NoteTCB interpolation is not available on the updated FCurves window toolbar. It can only be selected on the toolbar when you are in Classic Mode.
   

   FCurves window (detail) in Classic Mode A. TCB interpolation type selected for the keyframe selection

3. Edit the TCB interpolation by changing the value of the settings in the Tangent area. These settings let you change the tension, continuity, and bias of tangents. See Tangent area for more information.
   

   FCurves window A. Tangent area settings