Add water often enough so that the soil is never completely dry. It's okay if just the surface of the soil is dry. Don't add water when the soil is damp on top. Watering too often can hurt the plant. You may be able to buy a bulb that will grow quickly into a plant with a large flower.
Examples are calla lily and amaryllis.
Leaves will grow from the top of a carrot. Put soil or sand into a flower pot or any container that has a hole at the bottom to let excess water escape. Cut off the top one inch of a carrot. Bury it in the soil or sand with the green tip showing above the surface of the soil. Put it in a sunny, warm place and keep the soil moist.