The (small-o) orthodox version of Christianity has the following teachings among others: the Incarnation, Atonement, Resurrection, Ascension, and Second Coming.
The Incarnation is the belief that God became a human being in the womb of a virgin named Mary. This human being is called Jesus Christ.
The Atonement is the belief that Jesus’ death on the cross took away the guilt of all of humanity's sins, thus allowing people who believe in the Incarnation, Atonement, Resurrection, Ascension, and Second Coming to go to Heaven.
The Resurrection is the belief that Jesus miraculously came back to life after he died, which proves that what Jesus taught was true, including the teaching that there is life after death.
The Ascension is the belief that Jesus miraculously went up in the sky and, thus, vanished into Heaven. This supposedly explains why Jesus is not walking around the Earth nowadays.
The Second Coming is the time in the future when Jesus will come back to Earth and make everything right. True Christians will experience the eternal bliss of Heaven, and everyone else will be burned alive forever in Hell.
~ Jayson X, “What Was Leonardo da Vinci's Religion?”
(Jayson can't use his full name due to religious persecution which could threaten his employment in public education.)
When a christian tells an atheist we are going to burn in hell, we have some important questions to ask them. You see, the burden of their claims is on them, not on atheists. We do have the opportunity to ask them if they believe in Incarnation, Atonement, Resurrection, Ascension, and Second Coming.