To install plugin you need: 1) Copy files to \sublimetext_prettyjson. If you are not sure where is it located start Sublime Text and open Preferences -> Browse packages... In dialog opened you could copy path to plugins directory. For Windows 7 it is usually %APPDATA%\Sublime Text 2\Packages\sublimetext_prettyjson

2) Add key binding in Preferences -> Key bindings... like { "keys": ["ctrl+k", "ctrl+j"], "command": "prettyjson" }

3) Done, now select JSON and press Ctrl + K, Ctrl + J