Unfortunately calling the various panes in Music Maker by their location does not help as most of them are re-dockable and can be moved anywhere within, and outside when dual monitor working - the main window
Assuming you are using the default layout - as shown in the image below - right dock is the Soundpool pane and south dock is a multi purpose pane for the Mixer, Beatbox, Song Maker etc ,depending on the options you turn on - you cannot drop loops onto this pane.
The Soundloops should be add to the timeline pane.
For the correct names of the various panes see the manual available under Help.