World of Warcraft-->Professions-->Engineering
Engineering is used to assemble metal and stones into parts needed to make explosives, guns, scopes, bullets, mechanical dragons, aquatic helmets, and more. More than any other Profession, engineering products require several steps to be completed. Bombs and Dynamite are the bread and butter of the engineer's creations. Many engineering recipes require a lot of different parts before the item can be created. This will require more space in your bags than other Professions. Engineering is a very fun and creative Profession. You can create all kinds of wacky things that are fun to use and also entertain and amaze other players.
If you plan on being an engineer, you should probably already be a miner. Miners collect ore and smelt ore into bars to create the majority of engineering items. Engineer recipes often include jewels, which are found in a variety of places. Typically, most engineers buy or are given rare jewels from other players. Some engineer recipes require leather, which you will need to buy from a skinner. You will need to find a lot of other odd ingredients for your recipes that might need to be purchased from other players. Some items can actually be fished up with the fishing skill or found from monster drops or treasure chests.


Becoming an Engineer
First, you need to find an engineering trainer. You may have to ask other people where to find a trainer. After you have learned basic engineering, open up your abilities book (hit 'p') and look for the "Engineering" icon that has been added to your abilities.