Editing > Editing on the Desktop > Splicing Clips >
Splicing Clips with Audio

When you splice two clips with audio, use the Video/Audio box to specify how the audio is affected.

Select: | To:
--- | ---
Video & Audio | Splice the audio at the same location as the video. If the source clip has no audio tracks, the target clip's audio tracks are overwritten with silence.
Video | Ignore the audio tracks in the source clip. The audio tracks on the target clip are unaffected.

See Editing Video and Audio Simultaneously.