Using this ECOtanka Adapter Lid is a breeze. First, make sure your bottle is clean and dry. Then, simply place the adapter lid on the bottle and give it a gentle twist to secure it. When using it with a baby teat, attach the teat to the adapter lid. Remember, the teat is not included, so you'll need to provide your own. As for maintenance, you can wash the lid in warm, soapy water or put it in the dishwasher on the top rack. Always check the lid for any signs of wear and tear after a few uses. If you notice any cracks or damage, it's time to replace the lid to keep your baby's feeding safe and hygienic.