the responsibilities and administrations are yet to be seen. Nobody has been rewarded yet because the millenial kingdom is not here yet. Jesus did leave us some clues though. The parables he spoke gave subtle insights about his soon coming kingdom. One example can be seen in the parable of the talents.
Reference luke 19.
So from luke 19 we can see that the millennial kingdom will have countries, provinces, cities, and towns in it. And these countries, provinces, cities, and towns will have rulers over them. So again, depending on how faithful a believer was to the lord in this life, it will determine the level of responsibilty one has in the life to come.
So my advice to you is what jesus said to all who have ears to hear:
"lay not up for yourselves treasures upon earth, where moth and rust doth corrupt, and where thieves break through and steal: But lay up for yourselves treasures in heaven, where neither moth nor rust doth corrupt, and where thieves do not break through nor steal." matthew 6:19-20