I have purchased Premiere Elements 11 and need to know how to b-roll a clip on the time line...replacing video only on a a/v clip. Do I need to unlink the audio and video? If so, how please.
First, make sure you're working in Expert view.
Then add your main video to to Video 1 and your B roll above it on Video 2. Right-click on the video on Video 2 and select Delete Audio if you'd like to use the audio from Video 1 only.
This is one of the functions I cover, by the way, in my book, if you're interested.