Inside first
Move valuables away from the wet area and catch drips. If water is close to electrical fittings, treat that as an electrical safety issue as well as a roofing problem.
Do not improvise on the roof
Wet ladders, wind and loose tiles are a poor combination. A ground-level photograph is enough for the first call.
Temporary weathering can be sensible
A contractor may secure loose material or cover an area until conditions improve. Ask what remains to be done for the permanent repair.
After the rain
Once safe access is possible, inspect the surrounding roof rather than only the most obvious broken piece. Storms often reveal pre-existing weakness.