Gameplay/progression info for a newbie

[DarkTower]

This might seem completely daft for anyone who played PS1, but I couldn't find any information on this on the forums, but there's 2 main factors to me not understanding how the progression/unlock systems work:

Aside from killing people and a basic playing time rate, how do you actually earn XP? Having watched PS1 videos and from playing various games, I think I want to focus on driving or flying vehicles, probably a transporter (like the Galaxy?) to take troops to the frontline. Is there a 'thanks' system, or maybe one based on the other players' performance for a certain time after you drop them off? In other words, is there a way for me to earn more XP for doing well and helping my team while doing non-killing stuff?

As for certification points, what sort of things do these unlock? I know that PS2 is obviously going to have a lot more than PS1, but what sort of things do they do? I read somewhere that upgrades (i.e. +2% ammo) are only through CP while unlocks (i.e. different type of gun) are through CP or station cash), so does the progession system get more expensive the more you specialise, or is it similar whether you specialise or go for a broad range of skills/unlocks?

Also, will there be a 'reset' feature, to reset CP so that we can re-invest it? (I'm guessing you might need to spend money to do so?)