first thing to do is walk around the house with your phone and see what the strength is of the wifi signal.
at that good to low strength point, the distance of that location from the wifi signal source will give you a guestimation of the distance you can then go into with the extender. diagram S****M---E @Source/Mid/End
if the building extends beyond that point you should consider powerline repeaters with multiple stations.
wifi repeater must be in the good receive range to be able to repeat a good signal.
building material like what is in walls floors ceilings can impede wifi signals
it is BEST to have a wired connection from the main router to the extender. There is a lot of degradation in wifi as you doubly repeat it.
Most extenders have a number of possible configurations. Most you connect to the main router using WPS [button or software click].
Usually you assign it a ip address in the lan subnet but that is out of the dhcp scope so you can access via the lan to manage it.
This is all covered in the docs
Edited by Wand3r3r, 27 December 2015 - 11:54 PM.