This illustrates a step-by-step easy method for brewing Kefir. This is what I do. There are many other ways, too.
1.  Kefir should be kept at room temperature, lightly covered. I use a paper coffee filter and rubber band to keep out bugs but lets air in. This batch has fermented 24 hours.
2. When you're ready to use your kefir, you can use a spoon with holes in it to separate the kefir "grains" from the milk The grains look somewhat like califlower florets in a variety of shapes and sizes. 
3. A strainer also works well to separate out the grains. Here I am using a metal strainer. The grains are easy to separate out at 24 hours of fermentation. If the milk has turned into curds and whey, you can tell the curds from the grains by gently squeezing them. The grains feel like spongy tapioca. 
4.  Here the grains remain in the strainer and the fermented kefir milk is in the bowl. Some tiny grains may be in the milk but they are good to ingest also.
5.  Put the grains in a jar and add milk of any kind (dairy preferred). The jar can be used again and again before changing. The "good guy" bacteria in kefir overwhelm most any bad bacteria. (This is why many of us use kefir and kefiran (slimy coating on the grains) to treat our skin.)
6.  The thickness of kefir is usually about the thickness of a smoothie. I like to let the fermentation go to curds and whey, using the curds for sour cream or soft cheese.


Lots more information on Kombucha (and kefir)>