This answers some of my questions,
but I am looking for a tutorial that describing the way I mask text behind a person that is moving in front of the text.
Hope for some help whit this ???
So as to hide something behind your talent in a shot you need to do Rotoscoping.
See this tutorial from Mathias Möhl about using his Tracker2Mask script to simplify and speed up your rotoscoping.
See this tutorial about rotoscoping with Mocha.
You may either duplicate your footage and use rotoscoping data to cover some part of the object (text) in between
or create a shape matte (e.g. export Shape Date instead of Tracking Data out of Mocha and apply them onto a Solid) and use its inverted alpha channel to hide some part of the object (text)