The setup of the Time Capsule (Time Machine is software on your computer, not hardware) is relatively simple.
What is harder is getting the modem bridged properly.
I hunted around and you are far from the first person wanting to do this.. spend a bit more time with google.
http://community.talktalk.co.uk/t5/Computers-Gaming/D-Link-DSL-3680-in-quot-mode m-only-quot-mode-connected-to-Asus/td-p/908338
The instructions I copy and pasted from one post are even specifically for an apple router.
on 08-09-2013 09:00 PM
As I have multiple wireless devices providing a WDS (a repeating wireless network) network around my house / garden I wanted to ignore the Talk-Talk router and set my apple gear as primary router.
- Connect your computer to the Talk Talk wireless network using your web browser.
This is done by: http://192.168.1.1
- When prompted to log in to the router
username: admin
password: admin
- Goto the “Advanced” option.
The only change to make is: Change selection from PPPoE/PPPoA to BridgeMode
- Save Settings.
- Disconnect from talk talk wireless network and switch to your wireless Apple Network.
- Run Airport Utility and connect to your Apple Wireless Router.
- On the Internet Tab, change Connect Using to: PPPoE
- Account Name: 0123456789@talktalk.net (your talk talk account details)
- Password: your talk talk password.
- Select the Internet Options... button
- Change to PPPoE Connection: Automatic
- Save.
- Wire your Apple Router using an Ethernet Cable from the WAN port to LAN 1 on the talk talk router.
- Reboot both routers.
- Connect to your Apple Network.
- You should now have your apple router(s) providing your home wireless network.
- Optional: Press the WLAN button on the side of the talk talk router disable the talk talk wireless network. You can always enable it again if for any reason you need to connect to the talk talk router to reconfigure via http://192.168.1.1
