Here is the tutorial link
The tutorial skips the details of how to track your object with mocha.
For the details of tracking something in mocha see this tutorial:
Alternatively, you can also use the camera tracker, but if you have an object that you can track roughly in the area where your text should be, a mocha track will probably be faster and more robust. Using the camera tracker is only necessary, if the text should be floating freely in the air and you don't have any nearby object you could track. In your sample clip, you could simply track some leaves of the hedge.