@Guy-VV These aren't Sounpools but a song collection and sound effects. Simply extract the downloaded ZIP-archives and drag and drop the files via Windows Explorer or internal file browser into your project.
UPDATE: I re-read all the soundpools through 'settings', after decompressing the two zip files in the folder C:\Users\Public\Documents\MAGIX\Common\Soundpools\Shop. The soundpool with Effects now appears, but some sounds are grayed out and thus cannot be loaded.
Indeed, the other collection (Score - Classic Film Music) is nowhere to be seen.
Oddly, I also see some loops that cannot be used and where I see the logo of 'Loops Unlimited' at the back?
As @SP. posted above 'These aren't Sounpools but a song collection and sound effects', they are missing soundpool support files which provide information to the program on the specifics of the Soundpool.
Song collections and Sound effects should not be placed in the folder
they are missing the necessary support files that would make them behave as Soundpools.
Move the Collection and Effects loops into a new appropriately named folder within Documents, Magix, Music Maker, and either use Windows File Explorer or the Music Maker internal file explorer to drag the audio loops to the timeline.