1) on your grand father demise your grand mother , your father and his siblings were legal heirs to the property
2) if grand father had left a will your father should have enclosed copy of will, death certificate and made application for mutation of property in his name .
3) you and your mother should make an application before tehsildar for mutation of property in your names . enclose death certificate of grand father , father , death certificates . will of grand father ., your ration card , birth certificate
4) also enclose property tax paid receipts .
5) property will be mutated in your name and that of your mother after a month or so