What does each gesture mean — and which should I enable?

Start with Essential (🔴 only) if you want the most obvious alerts.

Move to Moderate (🔴 + 🟠) once your team is comfortable with the volume of alerts.

Use Max (🔴 + 🟠 + 🟡) for the widest coverage,

and Custom to tailor per camera. You can change modes anytime in Stores → Gestures.