The Mercku router arrives with an Ethernet cable, RJ45 connector.
In order for the WTFast software to work the Mercku router has to operate in router mode
Options:
If your wall port is regular Ethernet port you can connect the Mercku to it with the RJ45 connector.
Alternatively you can connect the Ethernet cable to one of the LAN exits of your ISP router and connect the other end to the Mercku WAN port - creating two networks in your home