Tcs Gym Policy

Just fill a medical form and sign it from a doctor and attend the gym from next day

I don't know about kolkata, but for tcs offices gym you need to fill a form which you can collect from security guard and submit it to trainer and start going to gym.
The most convenient way for you is to directly go to gym and talk with trainer. Timing is 6 to 9am and evening 4 to 8/9 pm