How are you trying to utilize volume up and down? From a dashboard? In an automated way? Or you just want to control volume? If you just want to control volume you can go to the device and use the buttons on the device edit page.
That user was specifically trying to use button controller (because I'm assuming they had a button remote). That's why they used button controller.
What are you trying to do?
If you have a button remote then button controller is probably the right direction. However, button controller is completely different in version 1.6 compared to 3.0. Today the instructions would be different.
- Install the button controller app.
- Click the "Button Controllers" parent app
- Click the "Create New Button Controller 3.0"
- Give it a name
- Choose a button controller device (choose the remote)
- You can prefill or click "Add a button action" to do it manually.
- Choose the action you want to use for volume. I'll choose single tap (pushed) button 1 in my example.
- Click the button it created (the highlighted section above)
- Select "Run Custom Action or Custom Command, Polling" from the action type drop down.
- Choose "Run Custom Action"
- For the capability choose actuator. This means that basically you want a device that is an actuator. When I created the device handler I made it so the receivers were actuators. Almost all devices that perform operations are actuators.
- Select the actuator to perform the action on (choose the zone device you want to change volume on)
- Select the custom command (volume up, volume down, setVolume)
- If you choose volume up or down you don't have to pass a parameter. If you choose setVolume you have to pass a parameter (integer) between 0 and 100 (just like the device edit screen
Then click "Done with the action" and keep clicking done until you are out of the button controller app. Test.
This process is outlined in the Hubitat documentation and I would guess numerous times here in the forum. If you have a question about built-in Hubitat apps in the future they are probably going to get fielded quicker in threads of their own in the support section of this forum.