Hi guys.  Going back about 2 years, i recorded a song and at that time i knew nothing about buses.  So i deleted the default buses you get when you start a new project. I recently sent the song into TAXI and they liked it but would like me to work on the mix.  Is there any way to put the Master Bus back into the song or is it gone for good once i deleted it?  Thanks guys. 

There's nothing special about the master bus, insert it like any other. The only difference is the master is routed to the hardware rather than to another bus.

Yep. Just put it back in but also note that you then need to send tracks or other buses to it.
My usual project has the Master(A) bus being fed by a "conductor" bus.
All other sub buses like bass, brass, woodwinds, strings, percussion, synths, guitars,  etc.  go to "conductor"
My master always has a brick wall limiter on it set to -0.1 dB so when I print a mix I'm sure there will be no overs.
Conductor will have compression a global EQ and sometimes a volume envelop to control long term dynamics in the piece.
 
 

Thanks guys.  Yep steve, that was my concern....the clipping.  I didnt know anything about this at the time so I wasn't watching my Master for volumes. 
cheers guys