Insert editing is quite easy if you have one of the recent video editing applications, many of which are listed on here. I don't know if Cyberlink can let you separate the video and audio tracks and let you edit each one individually? If it can then you are set to go, but if it can't you will need to purchase a new editor. Recording interviews is the best example of using this technique or adding in other shots on top of a music track. You lay down your audio track first and then select clips from the video to put over the top.

That's it at it's most simplest but if can get more complicated when you start chopping up interviews and you need to paper over the gaps, not only do you have to edit the audio track but you have to avoid jump cuts on in the video. in order to get shots to insert over the audio track, you have to listen to what the interviewee is saying or make a list and then go and record those items aswell so you can visually show what they are talking about. Cutaways, cut ins and over the shoulder shots need to be recorded and these all come in very useful when it comes to editing.

You can download many of the editors listed on this forum for a 30 day trial and see which one you like best. Look at Sony Vegas and Adobe Premiere Elements 7.