Mine has no buttons, it has a dial with the time marked all around it, with a bunch of slots on the dial. Then it has these red and green things (red off, green on) that fit into the slots. You set the red and green shits at the time you want your light on/off, plug it into the wall, set the time, plug in your light to the timer, an your good to go.
Shit, that sounds complicated.
peace