Referring to the virtual keyboard that is available in the file manager of Music Maker 17. Also, is there any detailed helpful tutorial for the program? I didn't find the one that the program offers too insightful.
You are right there aren't enough tutorials. But I have made some for MMM 16 Premium I am sure the command and functions for MMM 17 will be same. For Keyboard please refer this Pdf tutorial with image and text. You will know how to use Music Maker keyboard not an external one.
I have also read your other question. If you can play drum, guitar, Piano, Keyboard or synthesizer you can also connect them via usb to computer then make some settings in the Music Maker and record your own tunes. Or if you sing connect your mic sing and record vocals.