Diggle, like Google Slides and PowerPoint, has different presentation modes for different situations.
Like in Powerpoint, you can present in full-screen mode or use the backstage presenter and a separate display.
Presenting using a separate display gives you more control and predictability, especially in workshops with many questions and participants.
Read more about these options in Present using Fullscreen and Present using Backstage.
Look at our YouTube tutorial for a detailed description of both presentation modes.