You can read about Mumble here and you can download it here.
When connecting to the mypivots.com server, use the Mumble application (not the Murmur application).
These are the connection settings you need to use:
After you've started Mumble, click on the menu: Server > Connect.
Click on the Custom Servers tab.
Enter a new Custom Server:
Label: MyPivots
Address: www.mypivots.com
Port: 64738
Username: Mumble username (this is the username you registered with - usually the same as your forum name unless you changed it)
Password: your mypivots.com password
Save this custom server and then click connect.
Note: You must register your Mumble username into the mypivots.com Mumble database here, then you need to use the Username and Password you used in that registration process.