Hint message given while hovering over 'lock sticky key' in linux mint xfce is not telling how to enter in that mode.

I am new linux mint xfce user. Under system settings > Accessibility > keyboard we have use sticky keys option. It allows people with hand injury to use shortcuts like ctrl + 'c' first by pressing ctrl and after then 'c' (no need to hold both keys at once).

'Lock sticky keys' under 'use sticky keys' allows to activate modifier keys like(ctrl, shift, etc) to be active until it is deactivated by pressing same modifier key again.

Hint that is highlighted while hovering this section is not teaching how to enter 'lock sticky key mode'. To enter we need to press a modifier key like 'shift' twice and to exit we need to press 'shift' once. Example: If we enter in lock sticky mode by pressing 'shift' twice then everything we write will be in capital letters after that we can click 'shift' again to stop it. It was not mentioned in Xfce user manual also.