As I discussed in an earlier post, rather than denying death as does modern western society, medieval Christianity embraced it. Death was good, they asserted often enough and loudly enough that they may have almost believed it.
There was at any rate a fairly clear idea of what happened after death. Interestingly, the Bible never actually says that if we are all good little boys and girls we will go to heaven and become angels when we die (the New Testament talks about overcoming death, but there are no pearly gates or halos to anticipate). But once it became clear that the New Age that the Messiah was supposed to usher in seemed rather slow to appear, people settled on expecting a glorious afterlife, not a glorious life here on earth.
The straightforward version was that we would all lie in our coffins until Judgment Day, when the trumpet would blow (see the trumpeter on the right) and we would be judged, the sinners sent straight to hell for punishment by demons (as in this image), and the righteous gathered into Abraham's bosom. From the twelfth century on, those in the middle were sent to purgatory so that they could purge themselves from their sins through various sufferings. The idea of a third place, halfway between heaven and hell, had been around for a while, but it only became formally accepted in the twelfth century.
When you rose again, you got your body back. Although these days one expects to be a disembodied spirit after death, medieval people knew that when we rise, we rise in the flesh. (This is still orthodoxy; ask your pastor.) And it wasn't just any flesh, but specifically yours, all the dust and bits gathered up and reassembled. You would still be yourself, male or female as the case may be, but improved. Someone who had been lame would now be able to walk. Someone who had been obese would now just be pleasantly plump. Someone who had been anorexic would just be slender. The one thing that worried them was cannibals. Since "we are what we eat," they wondered whether the parts of a person which had been absorbed into a cannibal would be part of the original person's body in the afterlife or of the cannibal's.
Now all this happened at the end of Time, but saints were alive and with us right now, rather than having to wait around. Exactly how this worked was deliberately not contemplated.