If your function keys (F1-F12) are working but you don't see the volume bar on your screen, downloading and installing the specific Lenovo Hotkeys driver for your specific model (often an IdeaPad Gaming 3 15IMH05 or similar) is the fix.
Click . This will identify your exact laptop model and serial number automatically. Once identified, go to the Drivers & Software tab. lenovo lnvnb 16 12 16 drivers