You can upload your own world, we recommend FTP to do that, unfortunately 7 days to die saves are huge so it will take you some time to upload.
It is recommended to use Filezilla to transfer files between your computer and the server. Instructions can be found here.
Navigate to C:\Users\%user%\AppData\Roaming\7DaysToDie
Copy the world you want from C:\Users\%user%\AppData\Roaming\7DaysToDie\GeneratedWorlds on your personal computer to the \generatedworlds folder on the citadel server
Copy the same name from C:\Users\%user%\AppData\Roaming\7DaysToDie\Saves on your personal computer to the \7dtdsaves folder on the citadel server
Make sure in the configuration file "serverconfigmain.xml" that the following settings match exactly to the one you are copying
-Game World
-World GenSeed
-World Gen Size
-Game Name
Start your service
The above guide can be modified to move a server from another host as well. The files needed would be located in the same locations as your citadel servers 7 Days to Die server generally.
