Control Volume of AVR Denon Receiver in homekit

Hey there,
im totally noob to Home Assistant.
I currently managed to get the Denon into my homekit and it is working for changing inputs but i dont have a Volume (light indicator).
How can i get the ability to control volume?
Do I have to create a file / config .yaml?
If yes where? I already was searching google etc. but I dont get it working…
Hopefully somone can help me .-)