Hi Alison,
Happy to help!
You can achieve the fade effect and control exactly when your background audio ends using slide triggers. In the screenshot below, I used triggers to gradually decrease the volume of the background audio using the Player.BackgroundAudioVolume variable.
You can use a similar approach to slowly bring the volume of your background audio down to 0 just before the timeline ends. I've added a sample project file so you can see this solution in action.
Let me know if you have any questions!
