A fern is happiest when it's in consistently moist yet not waterlogged soil; thus, it's crucial to find the right balance between keeping it watered and not overdoing it.
The best way to know if your fern needs water is to check the soil. If it is dry to the touch, it is time to give the plant a drink, ideally during the early morning hours.
You can also check the weight of the pot; if it feels heavy, the soil might be saturated. Also, ensure you use a container with a drainage hole and loosely fill it with loamy soil.