Log in to the Kinetic Panel
Stop the server.
Go to Settings.
Locate the Map name box.
Paste in /Game/DLC_EXT/DLC_Siptah/Maps/DLC_Isle_of_Siptah to the box.
Start the server.
Conan Exiles guide
How to set the map to Isle of Siptah for Conan Exiles
This quick guide will walk you through adding the Isle of Siptah map to your server