There is only 1 version of Music Maker and that is Music Maker. You did not pay for it because it's free. You likely purchased an Edition, not the program. Which Edition?
When you start the program, Music Maker, you have to log in, if you already have an account, or join. Whichever, use the email address that you used to purchase the Edition. Once logged in, enter your serial number where it shows, and activate it. Then go into the program and download and install everything under the downloads tab.
If you are not logged in, you will always see the Free Edition.