I have four things that I think need to sorted out not three so here they are:
1.Get rid of the all corrput governments, i.e China, several African governments, Russia, America and several others (lightening and fire should cover it), and leave better, just ones and make up a council that is made up of impartial people (I might have to invent another country for this) that will govern over a senate made up of them and representives of each continent and country and big important matters will be put before the council and they'll decide what to do.
2.Give my father a lab and enough money to help him getting started and leave an edict that says "If this man comes before with something he has invented, then you will listen to him and let his inventions help you.".
3.Stop all war by sending the armies back to where they came from, get rid of those who wish to do people harm and fix the problems caused by that war. Then I write a law in stone that say's
"All world disputes here now and in the future will not be solved by war but by a representive of those involved in this dispute by duelling with monsters not swords." and I'll build an arena and put in robots made by technology from the future and leave behind information to repair and use them (again I'll entrust this to my father).
4.Repair the Earth by fixing the hole in the ozone layer, getting rid of fossil fuel cars and replacing them hydrogen fuel cell cars, replace the trees chopped down in the Amazon, putting back all the ice lost in the Artic and bring back all the recent animals that are in danger or extinct and leave monsters that kill anyone who try to hunt them.
Though I hope no-one makes a cult in my name. That'll be way too annoying.