Question: how to use fn lock?
Answer: Toggle Fn Lock If you don't, you may have to press the Fn key and then press an “Fn Lock” key to activate it. For example, on the keyboard below, the Fn Lock key appears as a secondary action on the Esc key. To enable it, we'd hold Fn and press the Esc key. To disable it, we'd hold Fn and press Esc again.