The Denon RC-1068 universal remote has an Amp button on the top left side of the unit. This button toggles through Amp, Zone 2, Zone 3, Zone 4 (on some devices) and System Call. In the Amp mode, it will control your Denon device default zone. If the remote is set to one of the other zones/modes, press the Home button (right side in the row with the Quick Select keys, above the surround sound buttons) to return to the Amp mode. Then press the Input button (on the left side), below the tuner buttons, to select the audio-visual source that you want.
See the manual for the remote at ManualsLib,
https://www.manualslib.com/manual/886505/Denon-Rc-1068.html#product-RC-1068 . The picture of the remote buttons is here:
https://www.manualslib.com/manual/886505/Denon-Rc-1068.html?page=2#manual .
I hope this helps.
Cindy Wells