How do I set the DSO trigger?

You can toggle the trigger on or off by tapping the trigger button on the right side menu. Once the trigger is enabled, the level is displayed by a red horizontal line on the graph.

To change the trigger type (rising/falling), tap on the left edge of the trigger line.

To change the trigger level, drag the left edge of the trigger line up or down. The exact trigger level is displayed in the information dialog at the bottom of the screen.