Hi,

A new midi file you mean like new project?

I do not think we can do this in Music maker but if want to open ready made midi file

Double click on Vita or Revolta 2 synthesizer

or drag n drop any one synthesizer on arranger.

Midi editor will be opened

Click on File/Import Mide

Note we can not save file as midi format.

This pdf will also give you some help

http://www.magix.info/us/about-bar-beat-metronome-midi-keyboard-in-magix.online-training.195529.html

Thank you

nihon94