Here are “The Bucket List” WoW achievement locations from Firelands.
You should first clear all the area (kill all the mobs and bosses before you reach Shannox).
There are some mobs that you can ignore though.
They are the ones that don’t attack you.
Then, once you reach Shannox pull and kite him to the places that are marked on the map (on the image).
It helps if you are a ranged class, especially hunters which are kiting masters.
Get some speed and avoid his hits.
Shannox hits pretty hard.
Once you move Shannox to all these locations, you will get the Bucket List WoW achievement.
Doing these achievements from old expansions can be fun when there is nothing else to do in the game.