Congratulations, Sir/Madam.
You have been randomly chosen as World Dictator, effective immediately.
Your word is now law, everywhere on the globe, limited only by the laws of nature.
Oh, there is one other limitation on your rule. It lasts for one year. At the end of the year every citizen of the world, aged sixteen and over, will vote on whether to execute you, or not. And no, there is no escaping this decision on your fate by clever loopholes, like outlawing the death penalty or redefining the length of a year, so forget about that sort of shenanigans. If you, for example, order that everyone aged over sixteen be killed, you are totally missing the spirit of this opportunity, and secret contingency plans will make you wish you hadn't been so, well, wicked.
When your time as World Dictator is up, the people of the world will be free to organize themselves as they see fit, once again. They can scrap every one of your innovations, or keep them, as they see fit.
Would you like you legacy to endure, when people see how well the world can be run, or would you just like to have a good time?
Your orders?