Using content maps from marketplace

I have some content from the marketplace which of course I add to the project. Besides the single parts there are some finished maps/scenes. I use these maps by simply double clicking on the map and the scene is there. I can add and change stuff, that is all fine.

Though when I save the project, close it and open it the next time, I must double click again on the map to both get the map/scene and the changes I made. So it saves the changes, but I must reload the map/scene every time I reopen the project.

I can only find one level.

Is it suppose to be like that? Is there anything I can do to make it stay?

In Project Settings, under Maps & Modes, you can set the default editor map and the default game map.

Thx that worked, but how does the map/level thing work. If I add more levels with maps inside and they are not the default/starting level, how do I attach level and map or how does the level map thing work?

The editor has a default map that it can load when you load the project along with the starting map file to load. If you have multiple maps in the same project then you will need to open them from the File menu to switch which one you’re working on.
In the game, you have to trigger map loading from Blueprints or code.