Welcome to pt, Gandalf85. :D I don't know if this is what you're looking for, but I'll have a go. This is about all I know on the matter:
There will be a final battle, in which, being the Children of Illuvatar, Elves and Men are destined to fight. Dwarves really have to as well, come to think of it. The Valar will intervene as well; they must if Illuvatars eventual perfect vision of Arda is to be fulfilled. After the battle, Aulë, Yavanna and the Dwarves (probably Elves and Men too) will restore the world to its former glory. After that will come the Second Music, elevating Arda to an unparallelled level of bliss, in which Men will participate, but Elves might not, as they will all have left Middle Earth fo Aman by that time (Aman no longer being on Arda). The role of the dwarves, not being of Illuvatar, is also uncertain.
I hope that's all correct, and that it all makes sense. Anyone want to add to it?
A mind full of fire and a fistful of steel.