Camping and defending are two different things, in my book. Not only do you want to get the enemy flag, but you want to prevent the enemy from getting your flag. Camping is where someone sits out in some remote location on the map waiting for an unsuspecting player to come by, or when somebody sits in the enemy base in order to pick off players as they respawn (spawn camping). Defending is where somebody is strategically positioning himself in order to prevent enemies from grabbing the flag.
That being said, I would advise against new players trying to defend. More often than not, it ends up hurting the team. If everybody is eliminated in the middle of the map except for Joe Newbie who's hiding in a corner by the flag, the other team will most likely be able to grab the flag and kill him before he has a chance to react, or worse yet, capture on him, giving the other team 5 points instead of just 1. The best thing a new player can do is rush out and either kill or die.
The other problem with newbies defending is that they start relying on 1-path maps where they can sit in one location and an enemy must pass by them in order to get to the flag. Then when a multi-path map comes up, they sit on one path wondering how people are capping on them and start complaining that the map sucks.