While specific icons may vary slightly by model, here is the standard layout for most Dell laptops (Inspiron, XPS, Latitude):
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. function key on dell keyboard