ET's Good vs Bad

Im sorry I am a bit confused. I do believe as many of you do that there are others out there in the Cosmos. My confusion is, which one's from which planet, as well as their dicriptions are the good ones and which are the bad ones? Also, how do you know for sure which ones are the good one verse the bad ones? I am sure I am not the only one confused here. Can anyone help out here?
Thanks
FREE HUGS
Janetta