Here goes some brief description from Wowwiki, and some instructional movies.

Archavon the Stone Watcher

Archavon the Stone Watcher is a quick raid encounter (like Onyxia or Magtheridon). This encounter requires two tanks.

This encounter with Archavon is a DPS race with only a few mechanics to watch out for:

• Every so often he will start shooting rock spikes at a random raid member. This person cannot avoid the damage (around 7k). However, they can damage other people around that person. Just make sure you aren’t unnecessarily damaging others or getting damaged by moving away.He will also randomly jump/charge towards a random raid member and leave a white cloud on the floor which will do ~2k nature damage per tick if you are standing in it. After he spawns the cloud he will stand still for a couple seconds then run back towards the main tank.Both tanks should be taunting every time their taunt cooldown comes up. There is no need to time the taunt with regards to a tank being picked up, as both tanks will have high aggro and there is no danger of losing the aggro lead as with the timed taunt strategy previously suggested on wowwiki. This also allows classes that are aggro mongers, such as rogues, fire mages and destruction warlocks to dps without fear, as they’re often the classes killed by Archavon using the old strategy.

It is common for players who have just recently won the Wintergrasp game to go straight down into Archavon’s vault for an attempt. Do your research on whomever you PUG and make sure they have a high sustained DPS.

Archavon is on a hard enrage timer (5 minutes) that will boost his damage 8-fold and immediately wipe out the raid if he is not killed quickly enough. It may seem harsh, but for the 25-man in particular, be sure to use the WoW Armory to check the stats of any damage dealers you recruit. Many raids concentrate on finding tanks with very high health and healers with 20k mana, but for this fight, the damage is far more important. As a rule of thumb, make sure all the raid members have 15k health (buffed) and all caster DPS has at least 16k mana. These are good indicators of a players gear, and the better the gear the better the damage per second.

• On normal difficulty, with Archavon’s health at 2,300,900 HP, the raid as a whole needs to output more than 7,670 DPS. As a good rule-of-thumb, with two tanks and two healers, the tanks should never go below 550 DPS and the remaining six members should stay above 1,100 DPS. Effective tanking requires a swap in aggro following the Stomp ability where he picks up the primary target for several seconds and then throws them across the room. This can be handled in a number of ways, though taunts are required as being picked up removes all aggro from that target. An alternative to the two tank method is to have a highly survivable dps grab the boss with a taunt and live through the several seconds until the tank taunts the boss back. A lesser strain on the healers can be achieved with taunting before the stomp is cast and thus being picked up instead of the tank, though the 0.6 second cast time on the ability makes this very challenging. On heroic difficulty, with Archavon’s health at 9,970,700 HP, the raid as a whole needs to output more than 33,236 DPS. As a good rule-of-thumb, with two tanks and five healers, the tanks should stay above 850 DPS and the remaining eighteen members should stay above 1700 DPS.

Emalon the Storm Watcher

Ten-man raids should use two tanks, two or three healers, and five or six damage-dealers, with ranged damage-dealers slightly preferred. Twenty-five-man raids should use two or three tanks, five to seven healers, and fifteen to eighteen damage-dealers.

On the pull, the tank (or tanks) for the Tempest Minions runs in first, closely followed by the tank for the boss. The boss tank taunts the boss immediately. Hunters and rogues can use Misdirection and Tricks of the Trade to help direct the targets to the correct tanks.

The boss tank and Minion tank separate to pre-agreed spots about 30 yards apart, so the Minion tank is not hit by Lightning Nova. Exact positioning is not important, so long as the separation is correct. Healers and ranged damage-dealers position themselves at least 30 yards from Emalon and in range of the Minions.

On 10-man, everyone must remain at least 10 yards away from everyone else, to keep Chain Lightning from jumping. On 25-man, it may be too crowded for this. Instead, stand exactly on top of one or two other characters, but at least 10 yards away from everyone else. This lets the Chain Lightning jump every time, but not far. Everyone must stay at least 10 yards away from the tanks.

The tanks’ initial threat is low as they get their targets under control and positioned. This is because they are moving and they need to avoid grabbing each others’ targets. Damage-dealers must wait until the tanks establish solid threat before they can attack. Once threat is established, they simply attack Emalon. There is no benefit to attacking the Minions until they are overcharged. They will constantly respawn

A straight melee hit from Emalon can cause 20,000 damage to the tank. Two hits in a row, without intervening heals, can kill many tanks. Having two healers on the Emalon tank makes sure that he gets healed often enough. The Minions do extra damage when they are overcharged, so the Minion tank may need extra healing at that time. The rest of the raid must be healed through Chain Lightning and (on 25-man) Lightning Nova.

All melee must run away from Emalon when he starts to cast Lightning Nova, then run back in to attack.

Emalon casts Overcharge on a strict 45-second timer. Use a timer mod (such as Deadly Boss Mods) to predict when he is about to cast it. All melee runs over to the Tempest Minions ahead of time. The overcharged Minion immediately grows to double height, and all damage-dealers attack it immediately, using whatever burst abilities they have. It must die in 20 seconds, or it wipes the raid.

Once the overcharged Minion dies, Emalon summons a new one near himself. The Minion tank must quickly pick it up. Having a third tank, while probably not necessary for survival purposes, makes picking up the new Minion more reliable.

The most common causes of wipes are exploding Minions, losses to Lightning Nova, losses to Chain Lightning, and losses to loose Minions.

To avoid wipes to exploding Minions, run a damage meter. Replace any damage dealers sustaining less than 2000 (10-man) or 2500 (25-man) DPS. If that is not reasonable, try positioning the Minions closer to the boss and rotating damage-dealing cooldowns (including Bloodlust/Heroism) on the overcharges.

To avoid losses to Chain Lightning, try separating and/or stacking as described above, or replace characters with low health. Having higher DPS also helps, as it allows the raid to win the fight before suffering too many deaths to the Chain Lightning.

Avoiding wipes to loose Minions is mainly a matter of tank skill. The boss tank can grab the Minion initially, until the Minion tank can pick it up. Using three tanks also helps (although this is not recommended unless your damage dealers have a very high DPS output).

Koralon the Flame Watcher

Right after the pull, Koralon begins to stack Burning Fury, giving the fight a soft enrage. Koralon does not have a hard enrage.

Because of his Meteor Fists self-buff (amplified by Burning Fury), you will need to use two tanks standing in one spot. The Meteor Fists damage will be shared between those two tanks. It might be useful when not using 2 tanks to have high health melee classes around Koralon so the tank will not face too much damage from the Meteor Fists.

Everyone must get out of the fire spots quickly. Tanks should agree on which side to leave by. The Burning Breath ability (amplified by Burning Fury), where Koralon spins around, cannot be avoided and must be healed through.

Due to the heavy incoming damage on both the tanks and the raid it is recommended to have 3 healers. Make sure you have either Fire Resistance Aura or Fire Resistance Totem up since most of Koralon’s damage is based on fire.

It is also highly recommended that all members of the raid have an Add-On like Deadly Boss Mods, which assists greatly in alerting one of the fire spots.