Clear the trash to the boss, the trash should be really easy to clear. I used to have trouble in non-tank spec but I had no trouble with the recent changes in WoD. Just clear the trash, kill them as fast as you can, some can be annoying. The core hounds will try to eat you, can be annoying. Work your way to where Alysrazor is,
this map will help.
There's two mage like mobs, kill them right away. Then kill the big fire birds behind them, then the little nests spawning baby birds. Then hit Majordomo Staghelm to start the fight.
After a small event he flys away and the boss spawns. Start DPSing the boss, pick up the feathers she drops. Sometimes this part will bug out and reset. If it does, you'll see a feather on the ground, click it to restart the fight. I've never had it reset after the initial one.
The feathers will give you wings, fly up with the boss. Follow her, going through rings while you DPS her. It's a lot like the new DMF game. It's really, really easy. She'll drop down every now and then, phase changes and such. Just ignore that and fly above her a bit, keep DPSing until she dies. Easy peasy.