VolControl is a free software to control volume from keyboard. Many keyboards already come with built-in volume controls, but in case your keyboard does not have that, you can use VolControl to manage volume.
VolControl lets you register hotkeys for volume up, volume down, and mute. It is a completely portable software, and runs in the background (even displaying tray icon is optional).
When you use those hotkeys to control volume, you can choose to display a volume bar that visually shows increase or decrease in volume.