I think they fill a Soda Bottle
, and then wait until it gets about as firm as an unopened soda. Thus there will be about the same pressure in your now carbonated cider as the soda. Then you would pasteurize, kill off the yeast and enjoy your cider. (don't use a water bottle, they are too weak.)
It was originally recommended that I try a bottle a day to check the carbonation and then cold crash or pasteurize.
Cold crash is generally done in the carboy, before carbonation, it puts the yeast to sleep and they hopefully settle on the bottom of the carboy, then you siphon the cider off the little bit of yeast.
Pasteurization is done in the bottle, generally with a hot water bath, and after carbonation if you want sparkling cider, before carbonation if you want still cider.
Hope that helps!