Your bad English is much better than our broken/bad Italian!!
I'm glad that it looks like he just overfilled the coolant tank. Keep a close eye on it.
This is how I test for a blown headgasket to see if combustion gasses are getting in to the cooling system.
This device sucks the air from the radiator or coolant tank and the purple fluid will turn yellow if there are combustion gasses present. They can be bought here for about $40.00
Combustion Leak Tester | Cooling | UView