How do i go about taking an ice bath.how much ice . and for how long. details?

Cold therapy:: Fill tub with two to three bags of crushed ice. Add cold water to a height that will cover your body to your waist when you sit in the tub. Before getting in, put on a down jacket and a hat and neoprene booties, make myself a cup of hot tea, and collect some entertaining reading material to help the next 15 to 20 minutes pass quickly. Water temp.: bet. 50-59 deg. Immersion time: 10-20min.