Seprate 5 on residential flat or including gst

GST is to be charged on total value of the flat/property sold.

Its bifurcation is to be specified in each installment to be charged.

If you have not segregated the value of flat and GST, the GST will be inclusive in total amount received from customer.

GST of 5% and 1% (effective rates) to be applied on taxable value. Normally when payment shcedule is planned there itself it is decided how GST will be charged.

If nothing is decided better to calculate as inclusive of GST i.e. whatever money you receive you have received inclusive of GST and back calculation will be done. Invoice will be raised accordingly..

The above will apply only when money is being received before issuance of invoice.