how to fix time machine backup failure?

I am telling you the whole procedure. Plug the ethernet cable in the Time Capsule's WAN which is Wide Area Network port, then just plug it in the Time Capsule. It will then begin to flash amber lights. Open your airport Utility application which has Mac and the Windows if it does not open automatically. The application will then automatically detect your time capsule which you have just plugged in. Follow the airport Utility's instructions for just setting up your Time Capsule. Here you can even choose to protect the wireless network which changes it's name, and then use Time Capsule to just extend the wireless network which you have already set up. Download any type of firmware updates for your new hardware. Airport Utility will then automatically install them after it has totally downloaded them. Choose your name which you selected in your Time Capsule setup as the computer's wireless network.