function keys

What the F Keys Do on Mac Keyboards
These are the primary defaults of what function keys do on an Apple keyboard when connected to a Mac:

F1 – Decrease display brightness
F2 – Increase display brightness
F3 – Open Mission Control
F4 – Open Launchpad
F5 – Decrease keyboard brightness (On compatible notebooks only)
F6 – Increase keyboard brightness (On compatible notebooks only)
F7 – Skip back (Audio)
F8 – Pause / Play (Audio)
F9 – Skip forward (Audio)
F10 – Mute
F11 – Volume down
F12 – Volume Up

The reference in the previous comment is what they do by default. If you want standard function keys, f1, f2 and so on, you have to hit the fn key. In system Settings/keyboard/keyboard short cuts/function keys, if you turn on use function keys as normal, or whatever it says exactly, if you hit f1, it will be f1 and so on, and in order to change volume or what have you, you hit fn and the function key.

Hi.

All third party keyboards are different. I know this because I'm in the process of buy a new ergonomic keyboard for my Mac. The f row key functions vary from keyboard to keyboard. However, generally speaking, it is true that the fn key is used to change keyboard layers. Each keyboard layer has its own key layout.

Now, in my experience, if you use an Apple Magic keyboard, the comment about media key layout is only mostly true; my Apple keyboard has some differences.

My advice is to familiarize yourself with your keyboard layout, such as by using your vo-k keyboard commander, by using sighted assistance, and by reading your keyboard's user guide. You might also google how to change your keyboard layouts, how to remap your keys, and how to edit your keyboard layouts and decide if you want any changes from what you already have. For any key functions you don't understand, search for the function in your Mac user guide and read what it says.

good luck!

Bruce