Hi there,
Drag the entire video to the secondary "Narration" audio track and click on
File > Save Movie etc...this will create a WMA Audio file. Create a new
project and put the video in place, right click its audio track and select
Mute, then import the recently save wma file and drag it to the narration
track. You then slide it back and forth until you get it as close as you
can to being in-synch. It would be a good idea to zoom in as far as you can
using the small plus symbol...it may help you identify certain peaks in the
audio.