From the Kefir starter package directions (this is what I do, works for me)
I've done milk kefir(I use organic whole milk), but prefer using the liquid of young coconuts - make a drink like a sour organgina.
"Into container (preferably glass with lid), mix together the entire contents of one foil package of kefir starter and one quart of slightly warmed milk (about skin temperature or 92 degrees).
Shake, stir or whip with a whisk to mix well. Put lid on container.
Let this mixture ferment at 72-75 F for 18-24 hours. (You will notice it is ready if the milk has thickened and has a distinctive, sour fragrance. Final consistency is pourable but not "eat with a spoon" thick.)
Once thickened, shake or stir vigorously and place into the refrigerator. Even in your refrigerator the fermentation process continues, but chilling will slow down the fermentation of the healthy bacteria and beneficial yeast.
* Kefir is usually made with cow's milk, but can be made with soy, coconut, rice, goat, or sheep milk (some varieties or milk yield a more watery kefir than cow's milk)."