1. Open steam
2. Locate ATLYSS in your library
3. Right click ATLYSS on the games list
4. Click Manage -> Browse local files
5. A file explorer should Open
6. Open ATLYSS_Data -> profileCollections
7. You should see a file called something like 'atl_characterProfile_0'. The number at the end is the save slot number
8. Check in game in which slot your character is and pick the correct file
9. You can now select that file on the website