garageband—basic editing

Open GarageBand. 

GarageBand requires you to select a project type.

Choose Podcast (1) and click Choose (2).

This is the podcasting screen. The first step is to simplify the interface.

Click the Edit button (1) and the Media button (2) to close those two panels.

This interface is less complex.

Select Hide Podcast Track from the Track menu.

The screen is even less complex.

Turn off Ducking. [Ducking is a way to automatically lower the background sound when the foreground sound is louder.]

Ducking is off and there are no ducking controls in the track head.

Delete all but one track—GarageBand requires at least one track.

Position the Finder Window containing the audio source files at the top right of the Finder window.