How do I clean my drains with baking soda? Someone told me it works great but I don't know how much to use.

Also, do I leave it there or rinse it down? Please clarify this for me.

Hair and goo can build inside your sink causing your drains to empty slowly, giving you something else to contend with during your bathroom cleaning ritual. Drop a couple of alka seltzer tablets into a slow drain and follow with a vinegar chaser. After a few minutes, rinse with hot water. Your drain will be as good as new. Would you like another bathroom cleaning tip? Baking soda will not only clear up clogged drains, but it will also keep them smelling fresh. Try this: pour one half cup of salt and one cup of baking soda down the drain and let it sit overnight. In the morning chase it with a pot (two to three cups) of boiling water....

I buy the little boxes of baking soda - and use about 1/2 of the box. Pour a cup of vinegar in and that's all you do. Wait at least an hour before running the water. If your sink has stains in it, sprinkle baking soda on the stains then dribble peroxide over the soda - give it a quick scrub then let it sit. Great way to clean your sinks and environmentally friendly as well as inexpensive.

You pour a little down the drain and pour vinegar on top. It will bubble up and clean out your drain.
I really don't have a measurement as to "how much", but it's better to start with less than to much because you could clog up your drain with the baking soda (I did it -lol).
you can always add more if it's not giving you enough bubble action.

use about 1/4 cup and let the hot water dribble slowly until the baking soda is gone. Then run the hot water strong for a couple of seconds to make sure it is all dissolved.