What to do when arriving ET

Expected to arrive during the time of our life and then what to do? 

The first thing that comes to mind is - do nothing - and the specialized institutions like NASA, European Space Agency, Russian Space Agency and the Air Force, and many other agencies around the world will be in charge of such contacts. 

But maybe there are topics that touch us individually, such as religious, do they have any religion they? Will they come to evangelize? Or more likely, they come to study us and colonize for their own purposes, or perhaps to take advantage of the natural resources of the earth, and the best to trade and exchange items, or who knows. 

Whatever it is, it will be a great milestone for us to know at last that we are not the only intelligent beings of creation ...