Can i claim or not??

I am the only child of my parents; I am adopted since my birth. My mother was 4 sisters and 3 brothers lived in a house owned by my maternal grandfather; she died in 2007; my father married a lady, and she had a son. My father died in 2017, lady left with her son and took `15, 00,000 from us after my father's death. Now, the house which was left by my maternal grandfather is about to sale (my maternal grandparents died before my birth). My relatives are sharing its value in 6; Whether I can claim my share or not? How can I claim it? What would be the procedure for this? What are the documents required?