In short, you add lots and lots and lots of bleach/liquid chlorine. LC is just double strength bleach that comes in 5 gallon deposit carboys. Easier to use when you are going through that much liquid bleach/liquid chlorine.
Your water goes through all kinds of amazing in hideous colors.
When it's clear and maintains a steady Free Chlorine level, you are done with the conversion.
If you have a sand filter, at this point you replace your sand.

Carl