1) on grand father death mutation of property should be done in name of grand mother . your mother can execute relinquishment deed to relinquish her 50 per cent share in property
2)enclose grand father death certificate , proof of payment of property taxes till date
3) indemnity bond and affidavit in support
4) if no objections are received property would be mutated in grand mother name
5) grand mother can then execute gift deed in your favour . it should be duly stamped and regd