Capture

Live view shows what the camera sees right now. Press capture to store that image as the next frame.

The onion slider lays the previous capture over the live view. Turn it up when you need a stronger ghost of the last frame, so you can see how far the subject moved. Difference view and a horizontal flip are on the same bar when you need another way to line up the shot.

Playback uses the same first-frame, play, and last-frame controls as the animation timeline, so you can check the sequence without leaving the workspace.