Snails are not particularly fussy eaters, you can feed them many different fruits and vegetables (they are particularly fond of cucumbers). Never feed them pasta, rice or anything salty. You will also need to provide a source of calcium e.g. cuttlefish bones (other sources are available).
Snails can lay up to 200 eggs at a time. If you do not want to be overrun with snails you will need to destroy the eggs humanely by freezing them for 48 hours before disposing of them. You should check the soil every few days once your snail starts to lay eggs ,which can usually be found at the bottom or side of the tank.