How do I turn on F Keys on Laptop

Hello,


I just bought a new HP laptop and am frustrated that the default setting for all the Function keys is whatever the manufacturer assigned regarding dimming/brightening the screen, changing volume, etc. For example, I can't hit Alt+F4 to close a window, I need to hit ALT+Fn+F4, and in Excel, I can't hit F2 to jump into the formula bar, but rather Fn+F2 to jump into it. How do I switch the default back to normal and get the manufacturer options if I hit Fn+ an F key?

Thanks for your help