It's a full functioning but cut down version of the Magix audio music production editor.Limited amount of usable tracks and instruments and audio samples as well as a few effects similar to those found in the MEP sound mixer.
You should find it in your program list as a separate program under the main Magix list.
Yes Sorry, non profit use, and after looking closely at EULA applies to sound samples and music tracks and any still images that may be found within MEP, not including fonts and the basic transitions and effects, (those not obtained separately via the shop whether bought or obtained via vouchers). Fades and effects within MEP are also OK to use commercially but unsure about some of the added limited function packages statuses such as Vasco De Gamma etc.
Commercial licensing for such use of those is on offer directly from those parent companies supplying shop content but sometimes those are hard to find.
From the menu bar at the top select Edit, Wizards there you will find the Soundtrack Maker as shown below
I assume you are new to Movie Edit Pro in which case I would advise you read the PDF manual available under Help, you may have to download it and watch the 'Getting started with Movie Edit Pro' series of tutorials by @browj2 in the Tutorials section of the forum.