Time capsule is another very cool thing that apple created, it can be used as an airport/router and as a wireless hard disk for backups even with time machine or just to store documents WIRELESS, it's useful if connected to the other router from the company that provided you the internet to extend your wireless signal more further in the house or just only to create a new network where only you can access . The configuration is very easy, you can either plug an Ethernet cable to your computer or to the house router and configure everything from: