1. connect modem to cable. 2. connect laptop via cat5 to modem. 3. go to any website, it will redirect to comcast registration. input account number input phone number follow onscreen instructions https://caap-cdca.sys.comcast.net/Activate/BrandingAction?checkboxClick=false now modem is good. 4. setting up router is a little tricky. one need power off/on both modem and router at the same time! ( i believe it's still modem first, router 2nd) now everythig is good!