You have two possibilities to connect the laptop to the Internet through the router. You can use a LAN cable without fear to configure something as the router is assigning IP addresses automatically or use the WiFi connection if the router has WiFi. You can turn on wireless on the laptop and check for the local SSID (network name) assigned to your router by the Comcast tech. Also, if the router allows only one connection per a computer, I am afraid you will need to contact the developer in order to obtain details about this.
