To repeat and extend the internet access of a router, you will have to pair at least one #dot to the router. The procedure is a 5 min step carried out only once, requiring a download of the #dotdot app: watch the tutorial video and get going!
Once done, you will have created a "root" node, which is the reference node for a WiFi mesh network. You may extend the #dotdot WiFi by merely adding more #dot's: just turn on a second #dot, and after a few seconds, its LED will turn blue, proving that it has found the root node and is connected to it! And you can repeat with as many #dot's as you want! Purchase your #dot's, download the #dotdot app, and off you go!