Your ISP may track your communication with tracker to see what your are downloading or block communication with tracker at all. The approach described uses an anonymisation proxy (JonDo) which will transfer all communication with tracker throw this proxy making you untrackable.
After you download both programs run them and go through the initial configuration. After you are finished open Vuze Options and switch to Advanced mode on the first page. Then type proxy in the bottom box. Click on the dimmed Proxy tab and configure it as displayed on the print-screen.
Save the changes and restart Vuze. If no error is displayed on start you should be fine and can start downloading anonymously 🙂