wld files in the tModLoader directory, and they should work as expected. Instead, tModLoader makes a new directory to store tModLoader worlds/players. Please keep in mind that tModLoader worlds are different from vanilla Terraria worlds. Once this is done, the next time you launch Terraria, you should have a tModloader Terraria! This is a pretty quick process, but if you experience any problem, PM me on Steam about the problem. You can check if you are root by running the whoami command in terminal. Make sure you are not running this command as root, as this will install tModLoader in a unexpected location.