How to create a Level 2 Folder

I know this is so basic, the answer is right in front of me, but I can’t for the life of me figure out how to create a sub-folder under my Level 1 folders. The only NEW folders created, either when using the Menu (Project>New Folder), or the folder icon at lower left with a + sign, are same-level folders as the one above it.

I can create new Level 1 folders and text documents under those folders, but cannot figure out how to create a Level 2 folder.

Help!

Select the folder then Documents > Move and move it to the level you want.

Or just drag the new folder into the other folder.