In later versions of Windows, it's not easy to edit the grub configuration file, since it can only be edited by the administrator. This means the editor must be opened as admin, then use File -> Open to open the configuration file (since drag and drop is tricky with admin privileges).
There should be a button in the GUI that opens the grub configuration file in notepad (or the default editor) as an admin.
In later versions of Windows, it's not easy to edit the grub configuration file, since it can only be edited by the administrator. This means the editor must be opened as admin, then use File -> Open to open the configuration file (since drag and drop is tricky with admin privileges).
There should be a button in the GUI that opens the grub configuration file in notepad (or the default editor) as an admin.