1) A router connects two or more networks and allows communication between them. It routes traffic between different subnets like a local network and the internet. 2) Proper configuration of a router is needed for networking and internet access. This involves settings like IP addresses, default gateways, and DNS servers for the router and connected devices. 3) Configuring a router typically involves accessing a web-based administrative panel to set up the WAN connection, local network, wireless access point, security, and other options like DHCP server settings.