I will git it a try, but we will try a easy and friendly way.

1.- Press song play, select the song with the F5 DIR and enter either the number or the first letter of song in keyboard.
2.- Is it ready?...ok, let say you wnat to change the tempo and as example, lets say is in 120 BPM....and you want it faster....well, press play and with the tempo button and increase it where you want it....( do not press STOP),
3.- Press F1 ( GM ).....you will see track #1 and wherever instrument is in there and the other parameters like volume, reverb, etc..., then with the page (hard disk/floppy), change the channel/track 2 or 3 or any.....there...(it does not matter)...press STOP.....WHILE you are in this mode, you can change the instruments ( from alto sax to tenor or brass, only need to press a different voice family and pick the sound of your choice....as longest you do not exit this mode, you may change ANY thing you want, when finish, press SAVE and then EXECUTE (F10), and like that you can save your new SONG SET UP, so everytime you recall that particular midi file, it will remember those instructions, by the way, also remember if you transpose the song ( MIDI FILE) or the Keyboard too.
Hope it helps....is easier than what appears.

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mdorantes