Imported Big Band MIDI appearing as loads of pianos.

I've gone back to Musescore 3 to try and import a big band score and get the attached—all parts as pianos.

I've been through this page: https://musescore.org/en/handbook/3/midi-import

I tried setting MuseScore instrument to ' — ' out of sheer clickerosity.

Anyone know how to just get an imported midi score with correct single instruments?

Thanks!