A WiFi Range Extender is a device that retransmits WiFi messages back and forth, emulating a WiFi client to the primary WiFi router and a WiFi router to the actual client. When connected to an existing WiFi network, it effectively extends the range of that network.
The added range extender should be positioned preferably in the middle between the existing WiFi router and the area that requires coverage.
WiFi range extenders can be very useful in solving coverage problems - extending the network beyond its original coverage.
However, when the required additional coverage area is large and requires more than one extender - a more reliable and simpler to manage solution is a WiFi Mesh Network System.