The location of the fn key on the first Apple wireless Bluetooth keyboard A1016

The first Apple wireless Bluetooth keyboard, Model A1016, which I just purchased, lacks an "fn" modifier key in the lower left. It is normally directly to the left of the "control" key, as it is on my MacBook Pro keyboard. But there is no key there.

I'd like to know where the "fn" key is, or how to make one of the many function keys such as F14, F15, or F16 into that key. I use the fn key via a double tap for dictation. (If necessary, when using that keyboard, I'll just change that method of activating dictation.)

It looks like this:

Thanks for any help. Please pardon my evident ignorance.

Kelly