PRODUCTION: Adding More Footage with Different Music

I wanted to add the next scene of my documentary into my iMovie but with different background music with it. I was struggling to do this because whenever I added a new clip the old music would extend over it. I looked up how to use different tracks on the internet and I found a really helpful video which explained exactly how to. This then allowed me to separate the video clips and put different music onto each. The video I used can be seen below.