It is on the top, literally (a small black rectangular button) if you Just want to sleep it then just press it; however if you want to turn it off then you should hold the button down and it will say slide to power off;then slide that and its off
NOTE: If you do turn it off, then it takes a real long time to get back on; however it slowly reboots your battery, unless it is completely out of power
NOTE: If you do turn it off, then it takes a real long time to get back on; however it slowly reboots your battery, unless it is completely out of power