Hold the button down to turn it on.
While on, hold it down until it flashes twice, and you can go through the recorded shots. Not sure what the limit is. Hold it until it flashes twice again to put it back to showing shot speeds.
Hold the button down to turn it off.
Don't lose the USB charging cable.
You're stuck in m/sec, no fps. Make a little chart or bring your phone for a calculator. 1 meter = 3' 3".