Setting a Custom Spawn or Lobby Location as a Server Admin
Editing the Datapack File
The teleport destination is stored in a datapack file that ships with the mod. Locate that file in your world's datapacks folder (or wherever the mod places its data). Open it with a plain text editor. Inside you will find the coordinates and the dimension the trigger sends players to. Change the coordinate values to the X, Y, and Z you want, and change the dimension identifier if you want players to land in a different world entirely.
Save the file, then run /reload in-game or restart the server so the change takes effect. Test it yourself with /trigger darkspawn before announcing it to players.
Choosing Good Coordinates
Pick a Y value that puts players on solid ground, not inside a block or falling into the void. If your lobby is a built structure, stand on the exact block where you want arrivals and read your coordinates from the debug screen. For a hub, a central tile facing outward works well. For a quest zone, place the point near the quest giver so players do not have to walk far.
Dimension Notes
If you point the trigger at a custom dimension added by another mod, make sure that dimension is actually loaded on the server. Pointing at an unloaded or removed dimension will break the teleport. Keep a backup of the original file so you can restore default behavior if something goes wrong.