The Add Audio Track dialogue box will appear to determine what type of audio track you want: mono, stereo, 5.1, etc. This will appear if you right click in the inspector area or if you select Add Track from the Project pulldown. If you don't want to see all of the presets, just click the Browse button and it will fold down to simple menu instead. Of course to bypass this you can always assign a Key Command to this action or setup a project template that has a few audio tracks already to go for you.
Cubase 8.0.10 / 7.5.4 - Cubasis & ICPro
Mac Pro Quad 3.7 Ghz 16GB, OSX 10.9.5
UA Apollo Twin Duo, G-Tech Raid, Novation SLMKII, True P-Solo, Numerous VSTi & plug-ins.