Any amount of light will work.
Soak the eggs in a little tap water for about an hour. Then add old tank water and start to aerate. Try to keep the temp around 78 - 80F.
They will hatch in 24 - 48 hours. Feed right away. After about 24 hours unenriched Brine Shrimp have almost no nutritional value.
To harvest hatched shrimp stop the air pump. The egg shells will float. the unhatched eggs will sink. The baby brine will be in the middle. They are attracted to light if you want to get them to congregate somewhere...