Summary of the concepts of Ahl al-Sunnah
The meaning of belief in the Last Day
is belief in the coming of a Day when a person will be held accountable for their deeds in this worldly life,
and then rewarded accordingly with entry into Paradise or Hellfire.
This is part of belief in the unseen.
And discussion of it encompasses everything that happens to a person from the moment of their death
until they enter Paradise or Hellfire and remain eternally in either.
It may be that some people are purified of their sins by entering Hellfire first,
and then they are brought out of it to the eternal Paradise.
This is on the individual level.
As for the level of worldly life and its end,
and the beginning of the Hour (Qiyamah),
it also includes discussion of the minor and major signs of the Hour.