Just bought one of these (v6 if that makes any difference

)
I'm going to connect it wired to my main PC, then once I've got that working stick a wireless card (WG311 v3) into my other PC and have my own little network
I've downloaded the manual and the setup looks seriously scary to me

!!
So: any advice from anyone who's used this box before on how to go about setting it up with my NTL BB ? Are there any options that aren't blindingly obvious that I need to know about ?
And most of all - if it all goes pear shaped and doesn't work, will I have to do anything to get my ordinary cable modem to pc connection back

??
Thanks