The latest raid dungeon, the Trials of the Crusader, breaks the general rule established by every other dungeon: Access to all the bosses in one lockout period. Pick a raid leader who has experienced the most number of Trial bosses or you could be stuck going through only the first encounter and have to wait a week for the second encounter, another week for the third, and so on until you have access to the bosses and the feeling that Blizzard is just trying to extend the lifetime of a patch that doesn't even come close to being as epic as Ulduar.
With my gripes done, we can cut over to the first encounter, the Beasts of Northrend. Similar to Mimiron from Ulduar, you'll have to fight several bosses with little time for rest before actually beating the encounter. Wipe at any point and you'll have to do everything all over again.
And if you want to start the encounters, talk to the NPC by the door.
Phase One: Gormok the Impaler
Two or three Tanks are needed for this fight. While Gormok has his weapon, he will cast Impale, a stacking damage-over-time effect that will put some serious hurt on the tank. When Impale is at three stacks, switch tanks until Impale wears off. Players with disarming skills should rotate their disarm usage to reduce the number of times Gormok can cast Impale on the tank.
Healers need to worry about two things: Staggering Stomp and Snobold Vassals. Staggering Stomp will interrupt your spellcasting, so shut those casts down before you're shut down. The Snobold Vassals are much more obvious, sticking to your head and beating on you like a Blackrock drum to interrupt your casts and stun you. If you're lucky, the Snobold Vassal will stick to one of the DPS classes instead.
DPS should always switch to the Snobold Vassals when they're out and about. Macro "/tar sno" if you have to, but knowing your hotkey for changing non-player enemies works just as well.
Listen for the "PAFF" of Gormok's Fire Bomb. You're more likely to hear it before seeing the ground under your feet light up (depending on your latency), hopefully without you in it. Run out of the flaming area quickly before you're grilled.
When Gormok goes down, tanks should get back to the entrance gate and be ready for the next phase.
Phase Two: The Twin Jormungar, Acidmaw and Dreadscale
If you hated the worms near Hodir in Ulduar or the ones in the Valley of Ancient Winters, you'll hate these worms more than just twice as much. And they're more than twice as huge.
Tanks from Gormok the Impaler should take position on each side of the large entrance gate, close enough to the wall to pull a worm and face them away from the raid to reduce the number of players affected by the worms' breath attacks.
Acidmaw and Dreadscale have two stances, stationary and mobile, alternating between the two after burrowing. Hunters should mark both worms to track their locations, making it much easier for the tanks to chase their targets. The worms lose their threat tables after surfacing, so tanks should be on top of them by that time.
The tank for the mobile worm will need to kite the worm around the arena to keep any melee DPS from dying to the poison clouds left behind.
Melee DPS should constantly be on the mobile worm. Any melee DPS that attempts to attack the half-burrowed worm will die quickly from the worm's 360-degree knockback sweeps.
Ranged DPS can choose between the two worms, but if achievements aren't the raid's priority, take down Acidmaw first.
Acidmaw will cast Paralyzing Poison on some members of the raid regardless of his positioning and Dreadscale casts Burning Bile. Paralyzing Poison lasts for 60 seconds and cannot be dispelled by any normal means. Burning Bile is a Fire DoT with a much shorter duration, but deals damage to anyone near the afflicted player.
Anyone who is afflicted with Burning Bile should run to players with Paralyzing Poison. If the only person with Burning Bile happens to be the tank, those with Paralyzing Poison should make the run instead.
After one worm dies, the other will enrage, increasing damage by 50%, hardly that painful compared to other paired mobs.
Phase Three: Icehowl
The Tank should get back to the arena gates and pull Icehowl close to a wall to cut any flight time spent after being hit by Icehowl's knockback attacks. Apart from taking lots of damage, the Tank should expect a lot of stuns too.
Healers and DPS should fan out, reducing the number of players frozen and damaged by Icehowl's random breath attacks. Melee DPS should be watch their health after being knocked back by Icehowl's Whirl.
Icehowl will occasionally jump towards the center of the ring, knocking everyone to the walls, dealing damage and stunning them. A raid warning will then pop up. Don't bother looking for the person in the raid warning. Watch the direction that Icehowl is facing instead and draw a straight and very wide line from him to the wall that he's facing. You should not be in that line. After the stun wears off, you'll have a 50% move speed buff to run away and clear a path for Icehowl.
If Icehowl hits the wall and is stunned, all DPS get a damage bonus to the yeti. If someone has a technological or mental malfunction and is trampled, Hunters should immediately use Tranquilizing Shot on Icehowl after enraging.