Create a new game on your server using the same Game Name and, (if applicable World Generation Seed), as your private game. This will make a saved game on the server, in the Saves folder. Then shut down the server, and copy your local game to that Saves folder on the server via ftp. You are replacing the new game you just created on the server with your local saved game. Your local game is saved in username /appdata/Roaming/7DaysToDie/Saves. Appdata is a hidden folder and if you can't find it type %appdata% in an explorer bar and it should open.
After copying your game to the server you can start the server and it should be live.