The behavior of these keys depends on your system settings. By default, most Dell laptops are set to prioritize the functions (volume/brightness). To use the standard F-key functions (like refreshing a browser), you must hold down the Fn key (located near the bottom left Ctrl key) while pressing the desired F-key.
If you press F3 alone, the volume goes up. If you press Fn + F3 , it performs the standard F3 function. function key on dell keyboard