Medium Light - Your mounted Staghorn Fern (Platycerium bifurcatum) prefers bright indirect light for 6 or more hours a day. Limit the amount of direct light it receives. An ideal location would be to hang it near a south or west window.
Water Regularly - Water this plant every week when the moss/soil feels dry. Before watering, check the moss with your hand. If the moss still feels moist, wait another 3-4 days to see if the moss dries and the plant is ready to be watered. Soak the entire mount, plank, fern and moss, for 10 minutes, then let plank dry thoroughly before hanging up again. Almost all houseplants will use less water in the winter than in the summer, so adjust watering frequency seasonally based on how the moss feels.