if you ask an active member, he or she will be more than happy to get a missionary to try to help you understand it, though the missionary version doesn't begin to cover it, either. You see, there are three Mormon heavens, and three degrees within each of those heavens, and different degrees of worthiness in a person's mortal life will qualify that person for one of those degrees within one of those kingdoms. (Got that, now?) "Saved" in mainstream Christianity is sort of equivalent to "exalted" in Mormonese, and those who will be exalted are those who will qualify, by virtue of their worthiness and having kept all of the Mormon commandments, including having participated in all of the Mormon temple ordinances, where the person learns the particulars of exactly how to gain entrance into that kingdom. It is only in that highest degree of the highest kingdom where God dwells and where "exalted" souls will also dwell for eternity (although they will also qualify to go and create their own planets/kingdoms/worlds, but that's a whole 'nother story).
See what I mean about being complicated and multi-layered? It takes quite a while to learn all of this stuff, so a truly simple answer really isn't possible in Mormonism. One of their complaints about mainstream Christianity is that it removed the "plain and precious" truths from the gospel, but I think they have it kinda backwards. In the New Testament the gospel Jesus taught really was plain and precious. It's good enough for me - how about you?