How do I make a new level and not a sublevel

I’m working on my first Unreal Projet. When I try to make a new level, Unreal seems to create it as a sublevel of the ‘‘Minimal_Default’’ level. How can I make full, independent level instead of a sublevel?

Thank you!

File - New Level.
The Levels window works like layers in a program like Photoshop so once you’ve created your main level, every other level is a sublevel. The only way to get an entirely new one is to go to File - New Level.

Thank you!