Are you still confused about some of the rules changes being instituted this year by the NFL? If so, below is a video released this past week by the league that goes over the rule changes as well as the points of emphasis.
The catch rule is addressed in this video as well and it uses Pittsburgh Steelers tight end Jesse James as an example. The video is over 11 minutes long but full of information. I highly advise that you watch it now that the preseason is underway.