A compressor like the Sonitus is like any other of the 1,000,000,000 compressors. All you need to do is leanr how a compressor works and you will know how to work every compressor. The same goes for every other effect, like Reverb, EQ chorus, and so on.
Learn about these things compressors:
Threshold
Ratio
Release
Attack
Knee
Auto gain
Input
Output
You can read more about them here:
http://www.audio-mastering-mixing.com/faq---q-a.html#22 Cj