I have imported a MIDI file and saved it as normal sonar.  There are many tracks on this and I notice there is no master bus so i can add a general EQ and master levels.  Is there a way to add this master bus once and route all outputs at one time to this bus?
 
 

right click on the buss area, either on the track view (bottom)  on the control view (right side).
got it?

You might also benefit from creating a number of sub-busses, where you can easily group & treat related instruments/voices without having to treat individual tracks.

In a rock scneario, it's common to have busses from drums/guitars/vocals/keyboards, in Classical you have Strings/Woods/Brass/Percussion and so on.

Bear in mind that the outputs of these busses must go to your master buss (the one you created remember?)

The point being that NOTHING should go directly to your main outs (Soundcard/interface) unless you know exactly what you're doing & why.

Great, thanks!