What happens next?

How to get rid of fungus gnats
Keep soil fairly dry.
Fungus gnat larvae thrive in wet soil. If you have plants that you water in pots or in your yard, don't do so excessively.
Many plants only need to be watered infrequently. If you aren't sure how often to water your plants, do an internet search or consult a gardening guide for recommendations for each type of plant.