Garrison level 1
Once you head through the Dark Portal in Warlords of Draenor, you can take a quest to start construction of your garrison.
You're going to be faced with a variety of choices, particularly when it comes to building your garrison for the first time.
While the process may seem like a complicated jumble of various bonuses and purposes, it's actually relatively easy to get your garrison up and running
In the beginning you’ll have a:
A flight master
So already now you will have 4 out of 10 buildings (21 in total to choose from)
As you continue to level, however, you're going to face more and more choices in regards to what to place in your Draenor stronghold.
Your first couple of garrison buildings are decisions that will be made based on what you already have going into the expansion. Upon creating the garrison, you'll be asked to create Barracks for your soldiers.
Barracks are just fine to start off with, because they unlock patrol missions for your followers that will get them more XP and get them leveling up more quickly -- which means they can do more difficult missions and bring home more cool stuff for you.
Your second building is going to be a small plot, reserved largely for buildings that are tied to professions. You'll get a quest item while you're leveling that will unlock the blueprints for a building associated with one of the two professions you already have learned. This is honestly your best bet for starting out anyway, because you'll want to level your professions while you're leveling out in the world, and a profession building will help you out with that process.
Garrison level 2
During the course of leveling along, you'll eventually find yourself able to upgrade your garrison to level 2. This will open up another small building plot for you, as well as adding a medium building plot. There are five different medium buildings you can build.
The Barn isn't exactly useful right out the gate for most players. However, a level 3 Barn will let you capture beasts and harvest Savage Blood, which is used for all epic crafted armor and weapons. Honestly, this isn't something you're going to need to worry about until you reach level 100, so you may want to pick something that's a little more useful right away -- unless you're planning on gunning for max level as fast as you can.
Is primarily for unlocking daily dungeon quests, and improving your followers. Again, this may not be really useful right at the onset of leveling -- although if you plan to spend a lot of leveling time in dungeons, this might be a really good option for you.
The Lumber Mill has you collect lumber from trees around Draenor as you're leveling. You turn in the lumber to create work orders, and the work orders give you garrison resources, which are needed for garrison tasks like creating and upgrading buildings or sending followers on missions. It's immediately useful.
This particular building is pretty much made for people that are going to be spending a lot of time doing PvP. The level one sanctum allows players to collect broken bones from enemy players -- something you're not going to find unless you're messing around with PvP combat.
This is your other immediately useful option. You can turn in trade goods -- ore, herbs and the like -- to create work orders, which will give you more garrison resources, much like the lumber mill. If you already have a gathering profession, this is probably a really good direction to go.
Garrison Level 3
At level 3 you'll get:
1 small building plot
1 medium building plot
1 large building plot
In total you will have:
2 large buildings
2 medium buildings
3 small building.
Here's what you need to keep in mind when you are creating buildings -- they are not permanent.
You can replace them at any time. Don't want a particular profession building? Swap it out for something more useful to you.
You don't really have to worry about picking the wrong thing, because you can always change your mind later if you need to.
At level 100, you can go to a vendor and buy the plans for the building type you didn’t choose back when you were questing there