Click the WHITE button to navigate between screens, until the word step near the top left of the screen as shown in the image below.
The Active step screen will show number of steps taken.
You will also notice an indicator bar on the left of the screen that shows your progress towards your daily step target.
The closer the bar gets to the top of the screen, the closer you are to achieving your daily step target. See how to set the Daily Step Target
The pedometer is designed to have the screen on all the time, it won't use any more power than a digital watch when idle.
To advance from one screen to the next, press the TOP button.