You will need to put in a sequence of notes that AMK can read, called "MML", into a .txt file. This can be done by typing it up manually with the MIDI as a reference, or by having the MIDI converted automatically with PetiteMM
. I will note that converting a MIDI with PetiteMM isn't going to give you all that you need; you still have the instrument channels to set up. Also, if your MIDI has paired chords in one instrument channel, it could mess up your MML.
Most of the questions your asking have answers that can be found on Wakana's tutorial
. It tells you the basics when it comes to setting up the instrument channels with the MML.