So, here is the Plan of Salvation, aka The Plan of Happiness. Refer to this cute drawing as much as possible during my description.
A long time ago Heavenly Father said, "Y'all need bodies like this sweet one I've got, but the process is complicated. If we decide to do this, some of you wont be coming back. Mortal bodies are subject to temptation, and if you sin you can't come back. Here's the catch, when you get your mortal body, you're not going to remember this conversation."
So Lucifer says, "Don't worry Pops. I'll make sure everyone comes back, because I will make them do what is right. But I want the credit and glory for doing so."
The Jesus (the brown-noser) says, "I'll live perfectly and atone for everyone's sins, and the glory will be yours Daddio!"
So this gets everyone good and pissed and a spiritual war breaks out. Thanks to Michael's fiery sword of destruction, Jesus' side wins, and Lucifer and his peeps get kicked out and sent to Earth never to receive a body.
(spoiler alert) Since you were born, it means you fought on Jesus' side.
As the illustration indicates when you come to Earth you pass though the veil of forget-i-ness, and your test begins. Hopefully you chose to be Mormon, and go to the temple for all your ancestors, because eventually you will die. Your body goes into the ground to wait for the resurrection, and your spirit goes to either Spirit Prison or Spirit Paradise (both are sill on Earth).
In the Spirit World people will continue to learn and do missionary work and if you decide there that you want to be Mormon cool, you can be (assuming someone living goes to the temple for you)(if no one does, don't worry, that shit will be straightened out during the millennium).
Then the resurrection. Everyone born is also resurrected. Which means your crappy mortal body gets turned into a bad-ass glorified immortal body and is reunited with your spirit.
Then we get judged. Pretty self-explanatory. If you're a dick your whole life, that might be something that gets brought up at your judgement.
If you're Mormon, and did everything you're supposed to do. You go to the Celestial Kingdom. If you aren't Mormon but still a good person you go to the Terrestrial Kingdom. And everyone else goes to the Telestial Kingdom, that's right, ever murderers and rapists.
In the 3 kingdoms you can travel around, but you can never go above where you were originally assigned. That means since my parents are good Mormons they can come down to visit me (since I'm a non-believer, but still an ok person) but I can't go up to visit them. We're told that the Telestial Kingdom isn't really that bad. Kinda like Earth is now, and it gets better from there.
There is something this cute little drawing doesn't show and that place is called Outer Darkness. You have to be a 'Son of Perdition' to go there, and that's really not very easy to do. We're told that the total of those who go there can be counted on one hand. You basically have to be a fallen prophet to qualify for Outer Darkness.
Good news, there is no Hell! No burning lakes of fire. No brimstone. No creepy clown demons like in the Spawn comics. There will just be an eternity of irony as you realize South Park was right and the only people in "Heaven" are the Mormons!!!