Every single day is necessary, because of the fact that it is a very small amount of soil, in a hot tent. It dries very fast. Neglecting keeping them moist will cause the seeds to die.
If the amount of soil was more, it would be every 2 or 3 days most likely, but the seeds like a lot of moisture, so less dirt is better in the beginning, in my opinion.
EDIT: I just noticed you asked how much water too, sorry I missed that. Not a lot, just use a spray bottle until the dirt starts looking saturated.