Since there is no input needed to "register" on a TeamSpeak 3 server there is no such thing as a manual registration in TeamSpeak 3. Basically once you connect you are automatically registered on the server you connected to. When you join again the server will recognize you.
Log into your server with the information you were provided in your setup email. You will see that you are a regular user. Open the permissions tab at the top of the page. You will notice a button that says "Use Privilege Key"
Click on the "Use Privilege Key" button and you will be presented with a little window.
Go into your email and locate the Privilege Key that was provided in your email. This will be the Privilege Key you put into the system. We suggest you copy and paste the Privilege Key from your email into the window.
Highlight the entire Privilege Key and then copy it. You will then want to paste it into the window that was opened when you hit the "Use Privilege Key" button in that permissions tab.