By default, it is recommended to assemble your levels with World Partition disabled and stream in and out different areas of the level as required.
You can have big chunks of your level in just one map but eventually, you’ll need to load and unload content to keep things into a reasonable budget.
For example, to start making a big level, you can start from an empty level. This will be your Persistent level on which you’ll load/unload different areas as the player progresses.
In your persistent level, assign the HE GameMode
Create a copy in your project (move outside of the plugin) of the HESceneTemplate map.
Open the Levels window from Window→Levels and drag and drop this new level into your Persistent level.
If you play the game now. the player will fall. This is due to this first area not being set to be loaded by default.
Right-click on the sublevel and change its streaming method to “Always Loaded”.