For CAG sanctioned events you would need the actual book (or electronic if in iBookstore) and the Updated .pdf file if it is an update. If it is a free .pdf from forgeworld AND is meant to be a replacement for what was in the book then all you need is the .pdf from FW unless it has a reference to the book then you would need the book.
The footprints made in the sands of time are not made by sitting down... Unless your playing Warhammer WAAAGH!
New times calls for new Records:
Orcs & goblins (3-1-2)
Imperial Guard (0-0)