How do you make an Audio file of an Aria file (personal Orchestra)? Then I wish to export as a mp3 file.
Jack the Quiet Bear

I'm assuming that you have it all nice in Sonar and can play it back.
If so, simply Select any track so as to focus on the tracks as apposed to any buses.
Then go: CTRL+A to select all, followed by File, Export Audio and select MP3 as the export format.
 
In order to do this though, you need the latest SONAR where the mp3 encoder is free, or the mp3 encoder license for lesser versions on SONAR.
 
 

Thank you, Bit man. Everything works just as you said. I was leaving out the Ctrl A even though I have used that in the past. Be careful about getting old you tend to forget things that you've already done.