1. Download any TBC 2.4.3 client. The official stance is that you have to have bought the client and used the CDs to install it, BUT they have no actual way of knowing and this was stated repeatedly.

https://www.burning-crusade.com/download/

https://s3-ap-southeast-2.amazonaws.com/calebolt/Vanilla243.zip

magnet:?xt=urn:btih:f9499fb1525f0dd23a19c4548805243632d420d1&dn=Excalibur+WoW+Burning+Crusade+2.4.3+-+With+Basic+AddOns&tr=udp%3A%2F%2Ftracker.openbittorrent.com%3A80&tr=udp%3A%2F%2Ftracker.publicbt.com%3A80&tr=udp%3A%2F%2Ftracker.istole.it%3A6969&tr=udp%3A%2F%2Ftracker.ccc.de%3A80&tr=udp%3A%2F%2Fopen.demonii.com%3A1337

2. Connect to the server

Go to https://www.rizon.net/chat

Enter a nickname

In the text box next to "Channels:", type: #corecraft

Connect

Type: !account

At the top left corner of your "irc window" there should now be a box with the text "ccbot" all in red.

Click on that and follow the instructions

Read the entire paste

3.

Make sure your realmlist is set correctly.

You need to edit your realmlist.wtf file (don't rename it to .txt).