Out of context, it's hard to say, but 'red button' suggests an emergency or 'panic' button. You'd hit this to say 'Stop!' or 'Get me out of here!'

it means that a person is probably in a critical condition and he or she must show a reaction to announce others.

hit is a verb which means click or press here. button is a stuff that u can find on most of machines, such as in ur keyboard, there are many buttons.

it means click the red button with ur finger if it is a real button or with ur mouse if it is a virtual button.