
I'm not familiar with that router, but would guess the MAC address option is to allow you to 'clone' the MAC address of your PC - useful with an STB (set-top box) where you had to register the MAC address. If you just pressed 'next' it would default to the hardware MAC address built into the router.
If you connect to the status page of the router, does it show a WAN IP address? (If so, don't post it in full for security, just post the first part, e.g. 81.123.x.x).