Make sure that you’ve marked the sync points for each camera’s footage before you attempt to synchronize them. You can mark the sync points by setting similarly numbered markers for each clip or by reassigning each clip’s timecode. (See Add markers and Set timecode manually for a clip.)
You can also use the Synchronize command
to sync several video clips on separate tracks or unlinked audio
and video tracks when you are not editing a multi‑camera sequence.