Usually it is done by taking steaming water in a bowl, then leaning over it to bring the face right above the bowl under a blanket cover to keep steam from escaping, then inhale and exhale.
The good thing is it is easy to do. bad thing is that you are steaming your face too instead of just the internals of the nose and lungs. The blanket cover with steam inside make you sweat heavily and the steam makes your facial skin pores bigger.
This method I am using doesnt need a blanket, is a bit more work to make it work, but it takes steam right inside through mouth and blow out through nose. wont make you sweat.
Step 1: Things Required
1) A Jar with mouth slightly larger than the diameter of a 500ml plastic coke bottle.
2) A small towel
3) A blade to cut the plastic bottle
4) A thick plastic tube. I am using a straw tube from an old water bottle.
Step 2: Cut Holes in Bottle
cut out 2 holes at the bottom of the bottle and two just below the shoulder of the bottle. In the pic, the holes are circled in Red.
Step 3: Wrap in Towel
Put the tube beside the bottle (I have put it through the bottle hole to position it easily. But it is not required).
Wrap both together in a folded towel
Step 4: Put Evrything Together
Insert the Wrapped bottle into the jar to make sure that it fits tightly at the bottle shoulder and that the holes cut into the bottle are not blocked by the towel. notice the depth at which the top holes in the bottle are. This is the high mark for filling water.
Remove the wrapped bottle, fill steaming water in the Jar until about an inch below the high mark noted before. Put the bottle back into the jar and fit tightly.
Thats it, ready to roll. Go ahead and use it as shown in the video. Inhale through the mouth and exhale through the nose.
you may add any medicine to the water as required for inhaling.
Step 5: How It Works
The Steam is strapped inside the Jar and the bottle as it is closed off by the towel. I accumulates at the top as it is hot gas. So when you inhale through the mouth of the bottle, all the collected steam is what you get.
This suction reduces pressure inside the jar which inturn sucks fresh cold air from outside, through the only available pathway - the small tube. This air accumulates steam and gets hot again, rising to the top, ready to be inhaled again.
You may coved the bottom of the jar with another towel to reduce heatloss so that you can steam for longer.