Once the light on the front is blue (and the DSL light on the back, if you have one, is green), it's time to activate your service. You can do this using the mobile app OR the QuickConnect site on a browser — either one will walk you through the steps to sign your subscriber agreement, finish installing service, and create your personal network.
Option 1: On a smartphone connected to mobile data, open the My CenturyLink mobile app, go into the Install My New Modem section.
Option 2: Plug a computer into your modem directly with an Ethernet cable. Open a web browser and type in to http://connect.centurylink.com (not "https"). Follow the steps to complete the installation process using QuickConnect.