The calendar covers when they are coming, though in our case we need also know:
1. how many are coming and composition (adults/kids)
2. when to pick up at airport or what hotel
3. cook or no cook (coordinate with our cook)
4. fishing or no fishing (coordinate with our guide)
5. equipment they will need (snorkeling equipment, fishing rods, etc)
6. special note (going on a tour, is it their birthday or anniversary (wife bakes a cake or welcoming pie or bread putting, special needs like a child pen, etc.
7. Pick up time (based on their flight out or going to another place.
So helpful to have all this in one place and at a glance.