In order to connect a router to a wired connection, you will need to add the MAC address to your account. Routers have many different MAC addresses. The MAC address you need to associate with your BlueRim account is often called your WAN or External MAC address (It varies by manufacturer).
Your WAN MAC is often on a sticker printed on your router or router's box. For more more specific information you will have to consult the documentation from your router's manufacturer.
For your convenience, here are links to the support pages of several router manufacturers support pages: