scheduler ?

Same way you would with any other controller. Just make certain the com port in the "settings" drop down match what port your USB dongle is plugged into.

If your screen goes black then it usually means you are using a video in your sequences and you have it set to output on the same monitor that you are running the scheduler on.  The "black out" is to prevent the scheduler (or whatever else) from appearing on the projector between sequences/shows.  If this is not the case then let us know... there are some things we can have you look at.

what kind of music file?

Because there are so many mp3 encoders (and not all are created equal), it is recommended that you use only .wav files as they are uncompressed and thus not prone to the same issues some mp3's have.  Aurora can read most mp3's, but there have been issues in the past.  If you need a .wav encoder, Audacity can export out .wav files and is also great for editing audio (and it's free too).

I do recall a few users having the black screen even though they are not using any video files.  This may have been caused by using a shared sequence that at one time had video, but some sequences created from scratch seem to trigger the full screen window.  Simply press ESC and the screen will return to normal, with the black screen reduced to a floating window that can then be tucked off to the side.

As you are still learning the ropes and testing what Aurora can do, you might benefit from reading the Unofficial Beginner's Guide and tutorial videos that ChrisL and I put together.  It's a tad dated now, but the information is still useful. 

Does your computer have dual-display capability? If so, try deactivating the secondary display.