A power adapter is required in order to connect and plug in the router to set up your Linksys AC1200. Now use an Ethernet wire to connect the router to the modem. Turn it on and watch for the LED light to come on to show if it's functioning. On a connected device, launch a Web browser, type "192.168.1.1" into the address box, and hit the "Enter" key. Enter the login information found in the User Manual and adhere to the prompts displayed on the screen. After adjusting and configuring the various settings, click "Apply". Restart your router now, then use your username and password to connect your devices to the network. Use the most recent version available for better and most efficient results performance of your Linksys AC1200 setup. For more minute details refer to the User Manual.