[Newbie] Animating with sound in mind

When I was growing up (twelve years old at first!), I made a bunch of really short animations in a program called MediaEdit Pro. When I was in high school, I tried out a pirated copy of Adobe Premiere, and I eventually bought it legitimately from my college (at an extremely reduced price, LOL).

I've since fallen out of the habit of making these kinds of animations, but I'd love to get into it again. One thing I always wondered about was how to make animations based on existing audio (like from a radio or TV show). Like, when you're taking the pictures, before you've imported anything into the computer, how do you keep track of how far into the sound file you are?