In reference to your query, please note that taxes need to be paid by you on periodic quarterly basis. I am attaching herewith the Official link for computation for your ease.
In so far as GST is concerned, not only is your turnover exceeding the basic limit of INR 20 Lakhs but also you are providing export of services which is a compulsory registration activity. However, in case of export of services, the Government has provided a benefit in the form of LUT, by executing which you would not be required to pay any taxes. However please do note that filing of returns would be mandatory.
It is suggested that you should take this registration at the earliest, as also compute your annual income and pay the applicable advance tax as the due date for 1st instalment being 15th June is already past.
Please advise in case of any further clarification.
Thanks & Regards,
CA Aditya Dhanuka.