If you have an Enduro 3, this watch has a MIP (memory in pixel) display and thus is always on unlike an amoled display. So I am assuming you are referring to the backlight instead. For this, go into the Garmin Connect app on your mobile device, select Focus Modes->Activity->Display Brightness. From here, you can either enable Gestures so that when you flick your wrist, the backlight will turn on or you can adjust the timeout as you see fit - perhaps even choosing no timeout at all (or do both). Note that greater use of the backlight will consume more battery. One can also adjust the brightness as desired.
