Setup to Combine 2 Airport Extremes via ethernet to extend internet connection

Apple Airport Extreme not only comes with beautiful design but also provides mac users with impressed Wifi performance improvement and security. If you have two Apple Airport Extremes, how to configure to setup and combine them via ethernet for extending your internet in both LAN and WAN connections?

Connect Modem or existing Routers and Airport via Ethernet cable

Apple Airport Extreme not only comes with beautiful design but also provides mac users with impressed Wifi performance improvement and security. A common problem you might encounter is how to connect the Apple Airport Extreme to your Modem or existing Routers via Airport ethernet cable. Look at our following instruction to do.