Answer to your question depends on computer system, normally Music Maker soundpools are saved in a folder called Basic

Program Files/Magix/Music Maker____/Basic_

for detail you can also refer tutorial given below. May be you will find some answers in it.

http://www.magix.info/us/soundpool-problem-and-solution-faq-for-mmm-16-premium.online-training.70780.html

Also note, in case of a download version after installation basic files have to download extra contents from Magix website.