Hi, I am Dave, I will help you with this.
If you have keys on your laptop for controlling the volume, they are not controlled by Windows, they are controlled by the PC manufacturer, because the function key actions vary from PC to PC.
If pressing the function keys for volume do not work if you press the Fn key + a function key, does that change the volume?
if it does, try pressing Fn + Esc to turn off the function lock on your keyboard.
If that does not solve the problem, boot your laptop into BIOS and look for a toggle switch to change from Function keys to Media Keys to see if that resolves the problem.
If those function keys are still not working, go to the support page for your laptop on the Asus website to download and install the ATK utility they provide for your laptop.