Bonjours,
Sur votre clavier il y a certainlyment des touches "1 2 3" et un bouton sous la sourie afin de sélectionner la clé unifying. If this does not work, check the "Logitech option" to make sure that you have connected your piano and source to your two unifying keys. If this doesn't work, try using the Logitech device.
J'espère que cela vous aura aidé.

Hello,
On your keyboard, there are probably "1 2 3" keys and a key under the mouse to select the unify key. If that doesn't work, look for the Logitech option to make sure your keyboard and mouse are connected to the two unification keys. If it still does not work, contact Logitech help.
I hope this has helped.