Off Whte How Do I Turn On A T-mobile Sidekick?

How do i turn on a T-mobile sidekick? - off whte

Seems stupid, but I do not know how to activate them. I have the power button and a screen with four buttons whte main approaches and do not know what to do from there. I always press random buttons until you activate it, but this time he came back and was not available for several hours.