Press keyboard numbers (or click agent's buttons) to unmute/show the tracks that will sound initially. Also to later mute/hide them.

With the Move tool: Drag any agent to change its volume and stereo panoramic. Dragging up will move it more far, smaller and lower volume.

The other tools are effects: Choose the desired FX and click on agents to activate/deactivate the effect.

Click play when you are ready to start the remix session. You can later edit your actions (as keyframes in a timeline) before or after saving your remix.

If the audio or the animation sync is not fluid in your device, open the menu and the "low CPU" dropdown to tune it for less demand