Inheritance

asslaamu aliakum mufti elias
i need some advice on inheritance.
1)my wife and i currently have no chlildren .in the event of either of us passing away who inherits from our estates.?
pls advise us in the scenario that our parents are alive and also if they not alive.aslo we both have siblings brothers and sisters.
2) once we have childred how do they inherit from us ?daughters and sons.?
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Kind Regards