Is there any source to learn step by step "How to evaluate different functions for a schematic circuit designed in virtuoso i.e- Gain, Vos, Pavg. and delay and so on" apart from the tutorial ?
The documentation Andrew pointed you to is quite good. I am not sure what your objective is if that does not meet your needs. However, there are numerous videos and tutorials available through a web search. The are not all produced by Cadence and hence may not be appropriate for the tool versions you have. Just as one example for some basic operational amplifier, there is video at URL:
However, please know I am not vouching for its accuracy nor its proper use of any Cadence tool.