When you enter the game Lobby you can see that you are able to choose maps.
These maps you can configure in the DT_Levels. Here you can set the name of the map for widget, actual LevelName and other settings for custom loading screen.
It is important to know that ALL multiplayer maps should be located in the /Game/ModernRPG/Maps/ directory of the project by default. This setting you can see and change here: