A WRE54G expands your network coverage into hard-to-reach areas. The installation of range expander saves wiring cost since this is doesn’t require an Ethernet cable after the successful installation.
For WRE54G v2 and v3, you can connect an Ethernet cable from the numbered port of your router to the Ethernet port on your range expander. The WRE54G v1 doesn’t have an Ethernet port so you need to connect to it wirelessly to configure it.
Complete install instructions here.