Like with addons in the current game, you just need to drop any of these addons into the addons folder — find it under /Interface/AddOns/ in the Classic beta folder, which is in your World of Warcraft folder by default. Then once you log on to the game, you’ll want to make sure that the addons are enabled via the menu option on the character screen.
As many of you know, leveling a Warrior in Classic is not easy - it’s almost like playing the game on hard mode. Despite having low mobility, low sustain, and the highest gear dependance in the game, Warriors are by far the most played class in Vanilla. There is a sort of masochistic appeal to leveling the hardest class in the game. To some, this epic challenge provides the purest Vanilla experience, and watching an expert pilot this class with finesse is like watching an artist at work.