Regarding ca final registration and elective subject

Hello All,

I have one query, I am planning to appear for CA Final Exam New Course in November 2019. Than when I need to register for CA Final Course? I have completed cleared both groups of IPCC and also completed 3 Years of Articleship and Advance IT Course.

I have also one query that when I need to select elective subject? whether at the time of enroling CA Final Course OR at the time of Filing CA Final Exam Form?

Please help.