1. Start from your rigged character and File>Export in FBX 2010.0 format
(character in t-pose, default export settings of FBX plugin with Y-up orientation).

6. File>Merge the downloaded FBX file back into Cinema 4D
A skeleton (B) identical to the one of your character but with the motion applied will be loaded in the scene. Selecting all joints, press the "key" button to make sure bothe skeletons have at least one keyframe on all curves

7. Copy motion onto your character skeleton
In the Timeline editor (Show F-Curves) select all the curves of skeleton (B) and copy them. Open the Timeline of character (A) after selecting all joints and paste the curves. At this point you can delete skeleton (B).

2. Select a motion model
- Mixamo has hundreds of online motions
- Many more being added each week

3. Design & Synthesize Motion
...using built in sliders and controls

4. Upload your FBX model
automatic mapping for standard rigs

5. Final Preview & Download
- Preview to your heart's content
- Only download when you're satisfied