Hey, in Cubase there are some icons, at the top left. one of them brings out the Mixer window.
You can use that. I used both the single track controls and also the Mixer window. Try out these symbols / Icons... in the upper left hand. If they are not there at all then this may be because you are using the Light version. I used the 4 Essential and and now the 5 essential version. One thing that is very important for your Mixing is to have the best possible Monitors you can afford. If you export anything then always as a .wav format and not a wma or mp3. The .wav format is uncompressed and should sound exactly like your Mix.