In both the Track View and Console View you have panes that show track and buses. Only in the CV can you see the "Mains" and it/they have their own pane. The buss pane may or may not have any buses in it. If it doesn't have a buss or buses the tracks will output directly to the main output. The main output is the input to your sound card going to your speakers. Even if you do have buses unless you have routed your tracks outs to a buss they will default to the main out.
Buses are made by the user and one can have as many as one wants. We have settled on a standard to route our audio and standard has one "master" buss. All other buses feed into this and it goes to the main out.
I like to have a buss for drums and one for instruments and one for voice. I also have an auxiliary buss too. I may have more than one aux buss. I use those for sends and returns. Each has sends on it that can be routed to any buss. Its a tap of the track signal that can go to an aux. This in turn will route its out to a buss, most likely to the master buss.
Again the master buss is used to have total control of and a place to insert final FX for the entire mix before it goes to the main outs. I leave the main outs alone. They stay at unity. What you see in the meters on the master should also be seen in the main outs meter. If not you have a mis-routed track or buss.
I think of the Sonar buss system to be the easiest and simplest system around and very versatile.