Cs info needed

I am a CPT passed student and have appeared for the IPCC exams (both group). I want to register for the CS Executive course. I have a few queries regarding this-

1) Do I need to undergo the SIP and ITT training before appearing for the executive exams? (I have completed my OT and ITT of ICAI)

2) What are the rules regarding the articleship of CS?

Some say that we can undergo it even after appearing for the CS final exams. Is it true? What is the duration then?

Thanks :)