These little critters are hermaphrodites--and no doubt yours had access to a partner before going in the bowl.
Hatching generally happens in 10-20 days, success depends on a tons of factors. No special care needed other than making sure they stay wet. They'll be readily visible on the glass and easy to remove if you start getting too many.
While large tanks often seen population explosions due to the amount of food naturally available in the way of decaying plant material, bio-film, etc. these sort of micro tanks typically balance out from any population boom very quickly. Indeed, under conditions of minimal to zero additional feeding being done (or high competition from other life in the bowl) adult pond snails will lay less and even eat their own egg masses, greatly diminishing the rate of reproduction.