To use this Purina Pro Plan Weight Management cat food, simply serve it to your adult cat as their main meal. Make sure to provide fresh water at all times. When you're switching your cat to this new food, do it gradually over a week. Start by mixing a small amount of the new food with their old food and gradually increase the proportion of the new food each day. This helps prevent digestive upset. Store the food in a cool, dry place, and keep the bag tightly sealed after each use to maintain freshness. If your cat has any special dietary needs or health conditions, it's a good idea to consult your vet before starting them on this food.