FLEX's Lift Intelligence means that there is no need to start and stop the recording of a set. However for some exercises you need a second to get into position (E.g Overhead press where the weight starts on the ground)
To set a prep timer press the icon in the bottom right hand corner of the screen. Select the amount of seconds you'll need to get into position. When you wake the device up the countdown will begin, no data will be recorded until the countdown is over. Once the countdown is over you're now ready to begin your set. We recommend that you have sound on as the prep timer gives you an audio countdown to assist you.