ltcg &sale of property throuh power of atterney

l intent to sell my plot to a builder for 64 lakhs,by executing sale agreement& power of atterney.In the sale agreement he has mentioned he will sell the undevided share of the plot in the same price as mentioned in the sale agreement.I have executed power of attorney to the builder,and received full settlement for my plot as in the sale agreement.Now kindly enrich me ,how the ltcg works on me.Advise me when I have to pay ltcg tax/investment to avoid tax,for the AMT I received.