First make sure you have Unreal.js installed. The marketplace version (0.2.0) can work. I am using the Github version (0.2.1) more information on the bugs section on why. Step 1 is to drags bootstrap.js and zThirdPerson.js into your Content/Scripts.
The market place version of Unreal.JS (0.2.0) has a garbage collection bug and will crash after 1 to 15 minutes depending on your memory size. I recommend getting the Github version (0.2.1) it is very stable.