Acer Aspire 3 how do I get my keyboard to light up in the dark?

Livingroom

Just set up a new Acer Aspire 3 but cannot see how to light up the key board at night

[Edited the thread to add model name to the title]

Puraw

https://community.acer.com/en/discussion/707596/acer-aspire-3-how-do-i-get-my-keyboard-to-light-up-in-the-dark

Keyboard Backlite is optional for some Aspire 3 models, most of the Aspire 315 don't have KB backlite:
Aspire 3 A315-510P Keyboard Backlight: No
Aspire 3 A315-24P Keyboard Backlight: No
Aspire 3 A315-35 Keyboard Backlight: No
Aspire 3 A315-21 Keyboard Backlight: No
Only the Aspire 3 A315-34 and A315-43 are listed with the Backlit keyboard as optional.