How to use MIDI Keyboard with Musescore

It's not needed to install any program.

Musescore by default was not using ALSA audio on my installation. It was only needed to select ALSA at preferences menu and it just worked!

to see if the MIDI was recognized just type aconnect -i

pauloh@mccartney:~$ aconnect -i
client 0: 'System' [type=kernel]
    0 'Timer           '
    1 'Announce        '
client 14: 'Midi Through' [type=kernel]
    0 'Midi Through Port-0'
client 20: 'CH345' [type=kernel]
    0 'CH345 MIDI 1    '

This last 'CH345' is my MIDI controller and it is shown only when connected.

To more details about MIDI I read this article from Rafał Cieślak