Whole bean is the best default if you have a home grinder: you grind only what you need, so the coffee stays fresher for longer. Store the bag sealed, away from heat and light, and grind just before brewing.
Match your grind to the method — fine for espresso or moka, medium for filter, coarse for French press — then brew as usual. Freshly ground Chasca beans show clearer sweetness and aroma than pre-ground coffee left open for days.