If you haven't seen the Beasts yet, don't worry! Healing the fights is extremely simple, and with just a little bit of coordination, you'll have them down in no time. For the Heroic Strategy, follow this link.
Gormok the Impaler
To start this fight off, pre-stack HoTs on the tank. There's not much else to do until he starts shooting off fire, so just keep HoTs rolling on the tank. The fire he shoots out is completely unavoidable, so be prepared for people to take a tick of damage when it lands. As long as they move out immediately, however, they should be fine. The fire sits in one place and doesn't move or follow you, so stepping out is simple. Stay at max range away from Gormok so as to avoid the silence from his Staggering Stomp, keep everyone topped off from fire damage, stomp aoe and face-eating snobolds (they quite literally seem to latch on like a face-hugger), and you'll have him down in no time. Tanks will be switching off with every Impale, but this shouldn't be too difficult to heal through. However, you will want to stack HoTs on the tank who still has impale going into the next fight.
Acidmaw and Dreadscale
This fight is like a tease to all who can remove poison. There's two poison types, a burning and a paralyzing, and the only thing that can remove the paralyzing is someone running past who is afflicted with burning to "burn" it off, or they'll be stuck in place, unable to move or act and taking ticking damage for quite a while. Since you can still move some while afflicted with the paralyzing poison, my guild had everyone afflicted run into the center, and the tank with burning would run over when Dreadscale was being range-tanked by our warlock (while he was sitting in the ground). Keep relatively spread out to avoid too many people being affected by the poison at once, and the rest of the fight is a snap. Roll Rejuvenations and Wild Growths on anyone taking damage, and they should go down quite easily. This is, in my opinion, the part of the fight that needs the most coordination.
This fight is pretty unique, yet still intensely simple. This is another fight you want to stay spread out for, since his breath attack can freeze whole sections of raiders in place. You can't control the direction, it's just something that happens. It doesn't hit too hard, so you should be fine. Keep people topped off from Whirl, and when he knocks everyone to the side of the ring and stuns them, look at the boss model. See where he is facing, and when your stun wears off, run away from that area. You'll have a speed boost, so for no reason should you not be able to get out of the way. If you don't, you die, simple as that. When he charges into the wall, he becomes stunned, so use this time wisely to top everyone off. Other than that, just keep people up from incidental damage and you should win this one easy. Also, watch out for Frothing Rage, though your hunters should smash that off right quick. If not, just heal, heal, heal the main tank!
That's it! That's all it takes. With only a few tries to coordinate poison, you should have them down in no time at all.