This will help you make it through the Hellfire Ramparts instance with a 5-person group.

You will need to find 5 players that are over level 61 for this instance, and make sure you have a healer and a good tank. This instance has three different boss encounters, but four bosses total. At the last boss encounter, you will fight two bosses. When you enter the instance, you will head to the first boss, which is Watchkeeper Gargolmar. He is a very easy fight if your team can work together well.

Here is the strategy for Watchkeeper Gargolmar: Have your tank attack him and then have two other members take out his healers when they appear. You have to take out the healers because they heal themselves and Watchkeeper Gargolmar. If you have a mage, or two, have them sheep the healers, kill Gargolmar and then kill them. While you are fighting Gargolmar, he will charge the farthest person from him and will do a ton of damage to cloth armor, so you need to keep someone behind your healer in mail or plate armor just to take the charge when it happens.

After you defeat him and the healers, the path will split. The right path will take you to Omor the Unscarred and the left path will take you to Vazruden and Nazan. You can do them in either order, but Omor is usually easier than Vazruden and Nazan.

For Omor the Unscarred, here is the strategy that you should use: First, pull the two guards that are at the entrance to his room. If you do this right, you won't pull Omor. When you get in to fight him, he will spawn a ton of felhounds that will head straight for your healers, but they die really easily, so make sure that you have someone to guard the healer.

There are two things that you should watch out for here, one is that he reflects some spells that can do a lot of damage back on your group and the other is that he likes to knock players up in the air and then juggle them with Shadow Whip. You should have someone or something that can help remove curses from players. He will put a random curse on players that can either be removed, or the player can move away from the group until it wears off. As long as everyone is paying attention and doing their assigned job, he goes down pretty easily.

For Vazruden and Nazan, here is the strategy that you should use: First, there are two Shattered Hand Scouts who are sentries of Vazruden. Once they are killed, he will come down, but Nazan stays up in the air. Nazan will throw down various bolts until Vazruden is killed, then he will come down and fight.

Overall, both are fairly easy to kill as well, everyone just needs to stay on their toes and watch out for Nazan's fire bolts, which leave patches of fire when they hit. This fight will take a little bit longer than the others because there are two bosses, so you will need to make sure that you keep someone protecting the healer at all times so they can continue to heal everyone in the party.

For Hellfire Ramparts Heroic mode, most of the boss fights are the same but just a bit harder.

Watchkeeper Gargolmar (Heroic): Strategy is same as normal mode just harder and he does stack a 10% healing debuff on the main tank which does make it where you have to kill him quickly.

Omor the Unscarred (Heroic): The Aura debuff does 10 times more damage so you must be well spaced out. The Hounds are harder to kill and they will mana burn.

Vazruden and Nazan (Heroic): Nazan does an AOE fear when landing and the fireballs that Nazan drops while in the air does around 2000-3000 damage and ticks for 4500 fire damage. So make sure to avoid those!