Now, touch the red alligator clip with your finger. Your body acts like an antenne and touching the clip will induce 'noise' to the input of the scope.
The unit will trigger and the display will show a single screen of the noise you've injected trough your finger. Next, the scope will switch to 'HOLD'-
mode. Now you have plenty of time to study the screen.
To capture the next event, press the 'HOLD'-button briefly.
Triggering is re-armed and when you touch the red alligator clip again, the screen will refresh: