Just press and hold the button. Then release the button when the status light turns on or off.

Thanks for the reply. I still wish Sonos went with a different approach with the power button, perhaps similar to the volume/content button (which could slide up or down to turn on or off and allow a press for bluetooth and other features). Granted, I would still have to remember that the power is on the left and the volume on the right. I still think that is a better adjustment, especially for those of us in the habit of putting on our headphones first (thus unable to watch a status light) and then trying to figure the right number of milliseconds to hold the button to power on.