i just had to do this due to my old linksys dieing on me.

info from
https://community.vodafone.co.nz/t5/...SL/td-p/172701
but there is a few bits of important info thats left out which i have added.

1. Open a web broswer (for example, Internet Explorer)
2. In the address bar enter http://192.168.1.1
3. In the Username field enter Admin
4. In the Password field enter VF-NZhg659 *Please note, if your firmware has been updated, the password will be @last 8 digits of the modem serial (the serial can be found at the back of the modem)

note- this has two different logins and passwords. on the back of the modem is the user account details which does not have the flash upgrade or dsl options in it. you need to use the admin account mentioned above.
the name and password is case sensitive.

5. Click Internet

The Internet settings page will appear

6. If there are settings under internet_vdsl and Internet_Ethernet, click Delete, otherwise continue to step 7
7. Expand New WAN connection and click Edit
8. Click Edit
9. In the Basic Information section complete the following fields:
• Tick the Enable connection check box
• In the Name filed, enter a name for the connection
• Service type: select INTERNET and TR069
• Access type: select ATM uplink from the drop-down menu
• Connection type: select IP routing (PPP) from the drop-down menu
• In the MRU text field enter 1492
• In the MSS text field enter 0
• NAT Type select NAPT

10. • In the Link Information section complete the following fields:
• VP/VCI text fields enter 0 and 100
• Link mode select PPPoA
• Service type select UBR without PCR
• Encapsulation mode select VCMUX

11. In the PPP Information section complete the following fields:
• PPP authentication mode select Auto
• PPP trigger mode select Always online
• Internet account field enter your Vodafone username
• Internet password field enter your Vodafone password

12. Click Save
13. Click Maintain
14. Click Device Management
15. Click Reboot

if you have screwed things up, you can flash the modems firmware by powering up the modem and holding the reset button for (i think) 20 seconds. then access the modem with your pc browser as above.