Lighting ??

Iv just planted some seeds in some peat moss under a t12 aquarium light for starting i was woundering how long the light have to be on pre day ? and how much do i water it a day its my first grow and im worryed about overewatering ?

lights on at least 18 hours a day for veg
now that can be 18/6 or 20/4 or 24/0

if you just started you don't need to water for several days, depending on how wet your soil was when you started you could go a week without watering