Slowly.
I have a large apple snail, about a baseball size. I feed it only with Romain lettuce. It survives well.
leaves!
leaves
Algae, so you don't really need to feed them as they "feed" themselves.
feed it
Nope.
there in water
Twice a day
Damp areas, with plants to feed on.
Throw it away or feed it to a turtle.
snail food