by buffing a team mate what does it mean exactly? if im a medic can i buff my mate up by throwing him med packs and will that give him more health or what?

That is the basic idea but you have to be relatively close.

yeah i get the idea but what will this do? how can i tell if i have been buffed? and what else can u buff your mates up with?

giving health(medic), ammo(solider), damage bonus for guns(engineer) and ops can buff command posts to give extra supplies

Medics increase your max health
Soldiers refill your Ammo
and Engineers make your weapon more powerful

Buffed health adds an extra bar on your health meter.

Buffed weapon makes your gun glow.

Extra ammo increases the number on your ammo counter.

pips for exp right?

Supply Pips are the number of actions you can perform.

One action, buffing health, giving ammo, buffing weapons ... takes away one pip.

I think he means if you use your pips to buff teammates you get exp from it.

Medic buffs(Increases) your health,he has an ability that lets him buff your stamina
Soldier increases your ammo,he has an ability which lets him hand out certain ammo types.
And Engie buffs your weapon damage from 10 to 20%.
Each buff removes a pip.