Keep watering the plants after they bloom. When the foliage yellows, cut the tulips back to the base of the plant with pruning shears or scissors. You may also be able to just pull up on the foliage to separate it from the bulb. Stop watering the plants and set the pots in a cool, dark location, such as a garage, until the spring. Take the bulbs out of the pots and replant them outdoors about 6 inches deep in a site that receives full sun. Water them well. They will come up the next spring.