Division of a property among brothers and sister

I am the only alive son of my father after my mother's death. My father married another lady after the death of my own mother. My step mother has four daughter and two sons. I constructed a building by my own earned money when my father was lived. My two step brothers also contributed some portion of their own earned money but almost one fourth of my share. Now my father died and my four step sisters and two step brother are alive. As per rule how the property along with building should be divided among brother and sister. On the basis of mother v/s mother .