How do I get to heaven?

I am going to the Air Force to become a Combat Controller here soon. I may have to eliminate some lifes and may not. I'v studied alot about religion. My Uncle is a scientologist, but I'm unsure if its christianity. Anyways, I want to be garanteed that I go to heaven. I want to do all good and be good. I use to be a Boy scout and my ways hwave made me up to this point in life. So I ask whomever is listening, how do I get to heaven?