Again I presume that yours is a co-operative society and not a condominium. In the case of the former the liability to pay municipal tax is on the Society. The Society will collect it from the member. In the case of a condominium the owner would directly pay his municipal tax.
You go to the municipal office of your ward and apply for a registration certificate. There are so many forms to be filled. They will be available in the municipal office. Fill up those forms and submit them along with the NOC from the Society. Keep with you xerox copies of all that you submit to the Municipality. Also pay whatever amounts are payable and preserve the receipt. Generally they are supposed to inspect the premises before issue of registration certificate.
Wait for a reasonable time, say, one month. If they inspect and give registration certificate, well and good. Otherwise you just start your business.
What all things, which you have as a doctor, you will know better than me.