When navigating through my files with my keyboard and showing a folder with RIGHT-ARROW
and then pressing F10 to create a new folder in that directory it does not create it there,
it is created in the folder I first entered with the ENTER key.

Using a mouse and going through the right-click menus does put the folder in the right place.
Is there a way to change this so the folder is created in the folder that is marked and showing with F10?

The action "Right-Arrow" does not enter the folder, you need to go into it with "Enter" so the subfolder is created there.

Sorry if I wasn't clear in my post.

When navigating with keyboard and you have a folder marked and press "right-arrow" it shows what is in the folder but does not enter it like pressing the arrow icon of a folder with a mouse..
Now if I want to create a folder in there with F10 I have to enter it.
But with a mouse I can just right click on the folder and choose create new and it is created in the marked folder.

I was wondering If the F10 function could be done like with the mouse right button menu when the folder is marked.

Maybe not a better explanation of what I'm looking for.