Shares between two wives children ?

Respected , When I was born my mother left immediately . Thus I am single child of my mother . After 4 Years my father got 2'nd marriage , & that wife-2 having 2sons. But she don't wanted me so my grand mother & my uncle adopt me & did my all as their children. before 2 years my father left, without making any will or written statement. Now that 2nd wife & her 2sons warning me take 7-8 lacs & give signatures on NOC from my side. But how I can do this? I am married 34 years old & having 1 daughter. Living on rent from last 16 years, I wanted to stand for my rights for my family . Wanted to ask u all respective that, what low says, after my father's death, how his property will distribute: (1) in 2 equal shares : my mother [on behalf her to me] & His 2'nd wife ? (2) in 3 equal shares : 1st wife[my mother] 's one only son[me] & 2nd wife's 2sons? & How could I claim for this? Also that father's second wife had hand over all my mother's jewellery and saying she don't having anything. kindly reply. Thanks.