Whenever I try to launch UE4 it takes me back yo my desktop

I downloaded unreal engines 4.12 through blood sweat and tears, I tried so hard only to find that whenever I click launch on epic games it just takes me back to my desktop! I try over and over again but its the same result!
I hope someone will give me an answer, but my computer intelligence level is novice so I would like whoever gets an answer to tell me specifically.

By the way my computer is an old vintage macbook.

I meant to say “back TO my desktop”.