[Sparktank]

Most NLE programs have functions that when you import any media, you can "link" multiple tracks together.
Video and audio are always on separate tracks and you can have multiple audio tracks.

It's different how each allows you to do this.
But once you import the video and audio separately, you should be able to select/highlight the two tracks you want joined by holding the "Ctrl" button down while left clicking on the tracks. And then either by right-clicking on the track you should see an option in the context menu for "joining tracks" so their statically linked to each other (as if you were to import them as a single file). Or the option is in the menu at the top somewhere.
I can't say specifically where, as I don't use APP.

But generally all NLE work the same.

You should be able to unlink the two as well.
And also link other audio tracks as well.
For instance, if you have a second audio track with sound effects riddled throughout the entire length and want them to keep in synch with the video and first audio track, you should be able to select all three tracks (1 video + 2 audio) and link together.

Some NLE's use the term "link", some use "combine", etc.

With Sony Vegas, I've always converted the audio to WAV and imported separate from the video and link them together.
Since most NLE's decide to convert the audio, anyway, (doesn't seem to have any option to "copy" the audio or use "smart rendering" the same way video has "smart rendering") I work with a lot of WAV's.