How to load level instance in game features plugin into main map to edit actors in UE5?

There is a map “L_AncientBattleGameplay” in the project ValleyoftheAncient at Plugins/GameFeatures/AncientBattle/Content/Maps.I can open it standalone but it only contains the logic actors. I’m wondering how to add this Level to the main map AncientWorld to edit this actors, because of we can not edit this in a pure empty environment by imagination. No documents and no clues, someone can help me?