Backups and Current World
Ark manages its world saves in a bit different of a manner than most games. These are typically stored in the fashion of:
But you will see many of these, they are date coded. To have a copy of your current world, you will download the original file, not any with .bak on them.
If there are errors in your world, or it won't start with the main one, you can delete it (This is permanent!!), and rename the .bak to the main. i.e. TheIsland.bak you change to TheIsland when you rename it.