OP it is hard to help you when you are so vague. Lets start with terminology.
dps: damage per second
There are 4 general roles in raids. DPS, healer, tank, buffer. Although specific bosses may have other specific roles, and some bosses do not have a tank.
What they do:
tank: Whoever has the highest toughness draws the ‘agro’ or attention of the boss. The boss will move to the tank (if the boss is mobile) and so the tank moves the boss around and faces the boss away from 9 other members of group. 99% of the time, the tank is a mesmer (with chrono spec), it is not uncommon for a tank to wear very high toughness gear such as minstrels/nomads, but some people prefer to go more glassy, with 1401 the lowest toughness most tanks will run with in unorganized groups, although speed clear guilds may run as low as 1085 toughness (last I checked). The tank is also responsible for all sorts of utility such as sharing boons, providing defense (through distortion), and group up enemies with pulls.
healer: The healer is responsible for healing the group after they take damage. Typically a ranger (with druid spec) fills this role. Many groups have thier healer bring a lot of healing power with magi/cleric or sometimes minstrels gear. The majority of damage is avoidable however (although not all of it), and so very skilled groups choose to bring more glassy healers such as vipers druid instead. Most groups you join, especially early on, will have magi druids.
dps: Their main objective is to attack the boss, do damage, and ultimately kill it. There are 2 main variants of damage that can be done; Power damage (also called direct damage) and condition (or condi) damage. Some bosses heavily favor one form of damage over the other, and so in order to give yourself more versatility early on, you must be careful which class you gear up for this role first. Typically this role is filled by elementalists, rangers, thieves, and engineers, but groups will also sometimes have necros,guardians, and even occasionally mesmers fill this role.
Warrior is a bit of an odd ball. Pretty much every raid group brings a warrior or two, and that warrior’s main job is to attack the boss like a dps role. However the warrior is brought because in addition to decent dps, the warrior brings several group buffs such as banner of strength. So warrior is a bit of a mix between dps and buffer role.
Buffer: This role buffs the dps classes and allows them to do more damage, by giving them boons. In particular the boon they give is quickness, as this role is pretty much exclusively filled by a mesmer. Usually groups bring 2 mesmers. The first mesmer is the tank (if the boss requires a tank). That mesmer is responsible for both tanking and buffing the group. The second mesmer is responsible buffing the group, but does not have to tank. Particularly skilled mesmers can also manage to do some damage while providing buffs to the group.
So, OP which of these roles do you want to play in a raid?
