can anyone understand a wireless repeater set up ?

hi guys

just purchased a edimax ew-7228apn wireless repeater and ive been trying all day to set it up.... however to no avail

basically i want to connect to a router 2 floors down ... however im not a expert on gateways,subnet masks and ipv4 addresses and its basically sent me crazy

all im trying to do is connect to the wireless connection then use the ethernet ports on the back of the device

ive run the set up wizard which seems ok until it asks you to enter the gateways,subnet masks and ipv4 addresses and this seems to be the problem.... as soon as i try to connect to the edimax ew-7228apn it changes to a unknown network

has anyone used this range extender and if so how did you set it up... a step by step guide would be much appreciated

note : im using a bt home hub but im connecting to my brothers o2 wireless router who lives in the bottom floor flat....

any ideas

cheers guys