Each task can detect the motion of only one character at a time. In the “Edit Video” panel, click the “Detect Actors” button above the viewport, and click the white bounding box to select or switch detection to another person in the video. The person enclosed in the green bounding box will be the one targeted for motion conversion.

For stepwise instructions on capturing motion for multiple actors in a single video, please refer to the Detecting Actors section in the Reallusion Online Manual.