Want share in my fathers property

My father makes second marriage after the death of my mother. From first wife he had two kids. Boy and girl. From second wife he had 2 kids both are boys. He is retired teacher and get pension. He had 2 houses and 1 open land and bank balance. 1 house is on my father and my brother’s name. 2 house is on my step mother and step brother’s name. Open land is on my father’s name. I am girl child from first wife, but there is nothing on my name How could I get my share.