Depending on how you like your meat, frying the burger will take between 2,5 to 4 minutes of frying on each side.
I like my burger meat medium to medium-rare. What I do is the following: I fry the patty on high heat in a pan with some oil until the patty becomes grey on the outside centre. Then I flip them, add plenty of salt and the cheese and remove the patty once the other side reached turned grey on the outside centre too.