HeyPK should chime in on this, since its his idea.
This is one of his explanations. http://www.aquaticplantcentral.com/forum/viewtopic.php?t=394
You cut the top off a half inch below the curved part.
Put in the soil.
Put in the plant.
Put in the water usually up to the soil.
Put the top back on with the top inside the seam so the condensation water drips back into the bottle.
Put the cap on.
Tape the seam with clear packing tape.
This is a maintenance free biosphere type of greenhouse. Just leave it on your windowsill. Its great for crypts.
Use a piece of oatmeal for co2 once a month and a piece of liver for nitrogen once a month.
Paul has had many other good ideas. He developed bleaching to get rid of hair algae. You really should ask him about his self sustaining co2 machine. It is an incredible invention! When I first heard about it I just couldn't believe it.