I have read RERA act and from that, I have one confusion for which I need clarification.

According to section 13 it says as follows:

(1) A promoter shall not accept a sum more than ten percent of the cost of the apartment, plot, or building as the case may be, as an advance payment or an application fee, from a person without first entering into a written agreement for sale with such person and register the said agreement for sale, under any law for the time being in force."

So if I am going to a developer to book an under-construction flat, do I need to pay 10 % of flat price as an advance+stamp duty as per local percentage+registration fee altogether and leave it to developer to deal with stamp duty payment on my behalf or I just need to pay 10% of booking fee and when the certificate of occupancy would be issued and the flat is ready for me to move in at that time I should pay stamp duty while getting the title transferred to my name?

And one more question - the said text from act says that 10% of booking should be paid while registering agreement of sales, So how does it work? Where do I need to go for that? By registering agreement of sale aren't we transferring the title of under-construction flat therefore need to pay stamp duty while booking a flat?

I am from Ahmedabad just in case if you need to know local law to assist me with this.