Hello and welcome.
Here you will find quick instructions how to install and set up mumble (voice comunication program)

First download mumble install package for your operating system, i recommend stable release, you can download from oficial site: https://wiki.mumble.info/wiki/Main_Page

On windows, use standart install method (click on the downloaded package, click few times next, then finish or something like that;)

when you first start the mumble program, audio wizard will appear. Please folow onscreen instructions and go through all steps. In this wizard u can set thresholds for mic voice activation, or you can just set up mic to push to talk mode and set activation key.

after that, in the main mumble window click server > connect, click add new,
Label: Sonic wow server ( you can fill anything here;)
Adress: archrulez.org
port: 64738 (default port dont need to be changed)
username: fill your name here (wow name preffered)
click ok

the server should appear in the favorite list, click on it and press connect

when you connect first time, there will be message, that the sever use untrusted selfsigned certificate. just trust me and press yes (or accept, or ok i don't remmember the mesage corectly sry;)

When you are connected to the server, right click on your username, and then click "Register"
This will create certificate for your acount and register your username on the server.
In the Configure>Certificate wizard menu, you can import or export certificate, u will need this if you wana use same username from several computers.

and thats all;) for more info use google or see oficial documentation