Once you plug in the router and connect to the router you may get a popup that asks for the username and password, close this box.
Once connected enter the router IP, 192.168.1.1 by default, into the address bar of your browser.
You will then see the web interface. Click on Sign In at the top right.
You will then be asked to sign in, the default credentials are admin as both the username and password. If the router has been preconfigured the password may be the serial number of the device. You may then be asked to change the admin password, you may wish to do this as it is advisable, however if you do not then click skip.
You should then be back on the main screen of the web interface, logged in as admin. Click the Gateway option.
You will then see the Connection Configuration page. Check the radio boxes at the top and confirm that VDSL is selected. If not then select VDSL and then click Switch Connection Type.
Once you have confirmed VDSL is selected, leave all the settings as they are and just fill in the Username and Password boxed with the information emailed to you. Once you have filled in the username and password confirm that the MTU and VLAN ID are correct.
Once you have done this click Save and then your connection will have been setup.