These apply when a clip is brought in, so changing them needs a re-import.
Open a video to pull out its anchor frames.
Edit an anchor, then preview its run to watch the motion drag it about.
A preview renders only the run of frames the selected anchor governs, so it comes back quickly. Render all bakes the whole thing.
ClackMosh is a datamosher. It re-encodes whatever you open into MPEG-4 Part 2 with no B-frames, so every frame is either an anchor (an I-frame — a whole picture) or motion (a P-frame — the instructions for shifting the previous picture about).
You edit the anchors. The motion is left exactly as the encoder wrote it, which is the trick: replace an anchor and the original video's movement keeps right on dragging your picture around. Delete one and the picture never resets, so the smear runs on into the next run of frames.
Clips added from the Clip menu are re-encoded to the project's exact frame and settings, which makes their frames interchangeable with the ones already there. Delete the anchor at a join and the incoming clip's movement lands on the outgoing clip's last picture — that is two videos moshed into each other rather than cut together.
Nothing is uploaded. Everything happens in this tab.