Airport Extreme Base Station - Config

Got one of these recently but cannot use it in anything other than OFF (Bridge Mode). This is because I cannot find any means of reconfiguring my existing Technicolour 582n to operate in Bridge Mode, so that I can set the Base Station to DHCP and NAS mode, thereby enabling all of the functions it can provide. My ISP said that Bridge Mode is "nasty" and wants me to get four block addresses and use two of them, one for the AEBS one for the Tech 582n - though how that works baffles me. One reason I bought the AEBS was its "simple set up" - not true in my case.