Widow ofproperty

my father dies in 1980 and left a property for which my mother , my brother ,my sister and myself are the legal heirs

all of us hold an equal share . now my mother and bother died  later , how does the property get divided ?. i have 3 children and 3 grand children ,my sister had 3 children and 4 grand children and my late brother has no children . he is survived by his wife .

please clarify this to me