The Nearest metro station is Harkeshnagar Metro station so you have clear idea now where to reach first by metro. It's very convenient to reach by metro than bus because availability of bus and time taken by them is unpredictable.
So this is a sample route from my place mayur vihar phase 1 to harkesh nagar okhla metro station which is on violet line. So you have to pick violet metro line to reach Harkesh nagar metro.
After reaching the final metro station, then there will be e-rickshaw standing to pick you to catamorph exam centre who will take fare of Rs 10/-
I hope you have understood the route now.
Best of luck for exam ✌✌