Your seedlings look ok for their age. You wanna know how often to water them? Check em three times a day. If the top 1/2" of soil is dry, lift the pot. Is is light to lift? Take a pencil and stick it into the soil 1" down. Did it come up completely dry? Then it probably needs water. How much? My rule is this: Water seedlings as often as they need it. MB once a day MS twice a day. You have to learn when they need water. Always water before the point at which the leaves wilt. If they wilt you waited too long.
When the plants get a little older water on a schedule...like once a day or every other....depending on amount of light