If you drag a shortcut to the Start Menu and drop it, you will get a shortcut on your Start Menu.
To add it to a Program group below the Start Menu, hover it there for a second or two and the group will expand.
You can then insert the shortcut into that Program Group.
A divider line will be displayed to let you know where you will be placing the shortcut.
To move a shortcut, left-click on it and move it to the new location.