Fade out, but not all the way out...

A noob question, but hopefully one that’s easy to answer:

I have a vocal and a music track. I want to start with the music at full volume, and then fade down (but NOT all the way out) once I begin speaking. At the end of the presentation I’d like the volume to fade all the way back up.

I understand that the ‘effect’ tab has fade in/fade out functions. But with that, the music fades all the way out. I don’t see how can I fade the music down to just 25% (or any other desired level) so that I can have quiet background music while I speak.

Is there an easy way to do this?

I suspect that you need the volume envelope tool.
I haven’t used it but you should be able to find instructions in thew manual

Thanks mikethebass,
Here’s a direct link: http://manual.audacityteam.org/man/Envelope_Tool