There are 3 types of rights a player can have:

• Player
• Moderator
• Administrator

Logout of the account, and in the player account TOML file found in /data/saves/<player-name>.toml you can modify or add the "rights" variable to the "variables" section. Valid values are "none", "mod" or "admin". Save the file then log-back into the game.

In game.properties you can set the rights property to your player name and then reload the server, whenever your player will log in they will be granted admin rights, even if they have previously lost them.

If you already have access to an admin account you can use the rights command to grant rights to other logged-in players. E.g. rights Zezima mod