Lopping or connecting one range extender to the other extender is very easy. This set up is usually imposed in the premises where you have a huge premises and the signals spread through main wireless router is very limited. Hence you might think of getting two extenders so that signals and range could be spread distinctively. However the set up of these two repeaters is bit complicated as the IP (internet protocol) tends to conflict.

https://my-wifiext.net/