Hello, this is a guide on how to get and install The Wrath of the Lich King. You will need a few things before you can install WOTLK including the following:

Note: If you already have the requirements, then please ignore.
These System Requirements:
Windows XP (Service Pack 3), Windows Vista (Service Pack 1)
Minimum: Intel Pentium 4 1.3 GHz or AMD Athlon XP 1500+
Recommended: Dual-core processor, such as the Intel Pentium D or AMD Athlon 64 X2
Minimum: 512 MB RAM (1GB for Vista users)
Recommended: 1 GB RAM (2 GB for Vista users)
Minimum: 3D graphics processor with Hardware Transform and Lighting with 32 MB VRAM (Such as an ATI Radeon 7200 or NVIDIA GeForce 2 class card or better)
Recommended: 3D graphics processor with Vertex and Pixel Shader capability with 128 MB VRAM (Such as an ATI Radeon X1600 or NVIDIA GeForce 7600 GT class card or better)
DirectX-compatible sound card or motherboard sound capability

Note: If you already have these, then please ignore.
Winrar: Can Be Found Here
(You DO NOT have to have wow classic or TBC in order to install this! This is a FULL install)

Download the installer straight from blizzard by clicking HERE
If you have a MAC, you can download the installer by clicking HERE
This will take a very long time, so save this to the desktop incase you need to stop. You can restart this downloader anytime you need to as long as you specify the correct locations of where you began to download the files.

You will also need patch version 3.0.2 to 3.3.5a
You can find them here:
(only download this one if coming from 3.1.3)3.2.0 (395 MB)
3.x.x to 3.2.0 (1.2 GB)
3.2.0 to 3.2.0a (8 MB)
3.2.0a to 3.2.2 (40.1 MB)
3.2.2 to 3.2.2a (8 MB)
3.2.2a to 3.3.0 (515 MB)
3.3.0 to 3.3.0a (4.86 MB)
3.3.0a to 3.3.2 (159.3 MB)
3.3.2 to 3.3.3 (122 MB)
3.3.3 to 3.3.3a (4.7 MB)
3.3.3a to 3.3.5 (23.7 MB)
3.3.5 to 3.3.5a (12.7 MB)

European Downloads (GB):
3.x.x to 3.2.0 (1.62 GB)
3.2.0 to 3.2.0a (8.14 MB)
3.2.0a to 3.2.2 (63.4 MB)
3.2.2 to 3.2.2a (8.12 MB)
3.2.2a to 3.3.0 (644 MB)
3.3.0 to 3.3.0a (5.37 MB)
3.3.0a to 3.3.2 (180.65 MB)
3.3.2 to 3.3.3 (157 MB)
3.3.3 to 3.3.3a (4.98 MB)
3.3.3a to 3.3.5 (20 MB)
3.3.5 to 3.3.5a (12.6 MB)
When it tries to auto-update, quickly cancel it and install the next patch..
MAC clients will have to find their own patches. Sorry!

You will need to change you realmlist.wtf file to our servers ip. In the new WOTLK and 3.0.1+, they had moved the file to a new location.
If you installed to the default location, it is in C:\Program Files\World of Warcraft\Data\enUS\
Now, if you installed a different language version, the data folder will be different. For example, if you installed the Great Britian client, then the folder would be labeled something like enGB.
Open your realmlist.wtf with a notepad by either dragging it in a notepad file or by selecting it to be opened with notepad. Inside, make it only say the following:
set realmlist tfaconnect.org

Make sure you save and exit. If you for some reason cannot save it within that folder, save it to the desktop. After you save it to the desktop, then copy it to the folder where the realmlist.wtf is located and replace the current one.

Delete the World of Warcraft on the desktop and go to your World of Warcraft folder and right click WoW and say send shortcut to desktop. This will prevent any auto-updates in the future.

Creating an Account (This step is for if you do not already have an account.)

Go to http://www.tfaproject.org/create.php
Read the Terms of Use Agreement
Create an account by entering in a usename and password

Start up the game by clicking on the shortcut you placed on the desktop and enjoy the game. Thanks for helping the TFA Project. Report bugs to GM's by submitting Tickets.