For dinghies up to 40 HP no boating licence is needed: an ID and the initial briefing are enough. For higher power a valid boating licence is required.
Usually: briefing with a map of the coves, safety equipment, sun canopy and cool box. Fuel and deposit are almost always separate — check the listing for details.
The briefing shows the sheltered areas where you can navigate safely with each wind. In case of prohibitive conditions the operator reschedules or refunds the rental.