Original file for UE4

Hi, I’m new on UE4 and I downloaded the software in the file Applications (I’m french so my files are too, I don’t know if the file in english got the same name) thinking that I will have a short cut to launch it but I got a bug with the software what is I think due to that. So please, can you say to me what is the name of the file where is placed UE4 at the beginning ?
Sorry if you don’t understand what I’m talking about, ask me if you don’t understand I haven’t got a very good english.