How can I desalinate salt water into fresh water
take the salt out of water
To remove salt from water, you need to use distillation method. With this, you will have to boil the water and collect the vapor in a separate container. This collected water will be salt free. Read more on http://chemistry.about.com/b/2010/01/01/how-do-you-remove-salt-from-water.htm.
Boil the water, and the salt will be left behind
Evaporation &/or filtration. aka. reverse osmosis. (A complicated but effective filtration method.)
through some chemical reaction you can precipitate the salts dissolved in saline water and purify them or extract them they are byproduct. Secondly you can distill the water so as to get salt free water.