Set up your Terraria server

Core options (serverconfig.txt)

1. worldname names the world; maxplayers sets the slot count (up to 255, but size it to your plan).
2. password makes the server private.
3. difficulty selects 0 = Classic, 1 = Expert, 2 = Master, 3 = Journey for newly created worlds.
4. motd is shown to players when they connect.

Load an existing world or auto-create one

Point world at an existing .wld file to load it, or set autocreate (1 small, 2 medium, 3 large) to generate a new world on first start. Do not set both to conflicting values.

Plugins require the TShock build

The vanilla dedicated server does not load plugins. Server plugins need the TShock server build, which is a separate, validated server type rather than something you drop onto vanilla.