How often and how to water?

Okay so my first grow attempt ever went not so good but a learned quite a bit.
The roots came out of the top of the soil and were redish brownish and the plant was dieing so i scrapped it :S

My question is when I put my germinated seeds in the soil should I just spray them with a mist can and how much water should I give the seedling approx (in ml.) I'm using miracle grow fertilizer with a little mixed perlite.(haven't added anything to it yet because I don't know if it already has everything it needs [i didn't open it yet] And when should I start actually pouring water into the soil and how much should I pour when I do start.

Seeds need to be kept damp, not wet. Just misting once in a while is fine depending on how hot it is and what lights you're using. Once they push through the soil still just misting will work till they get a couple inches. Cannabis requires oxygen to the roots. Thats why you can't keep them wet like you would with most other plants. Generally once they're up and healthy and a foot or so tall, just soak them once a week with water and nutes. Again depending on light source and heat.
Its a learned technique. Learn to the lift the pots when soaked to learn the weight and then lift them when they're dry. Sometimes you can wait till they are just starting wilt from lack of water to gauge when its time to water them.

Alright thanks a lot. I think my first grow attempt went wrong because right from the start .. I put about two inches of perlite on the bottom of my bucket then soil on top of that (and didn't mix it) and I kept watering it heavily once a week and the roots were a red/brown color.
I think that was my mistakes - that and fertilizing it too early.