TP-Link RE350 AC1200 Manual page 16

TP-LINK_Extender_2.4GHz or _5GHz.
For Mac OS X users:
Unplug the Ethernet cable from your computer (if any).
Click the Wi-Fi icon on the top right corner of the screen, and connect
to the extender's network:
TP-LINK_Extender_2.4GHz or
Login
Launch a web browser and type http://tplinkrepeater.net into the URL
field and use admin (all lowercase) for both Username and Password to
log in.
Configure
_5GHz.
Create a new username and password to log in the web
management page, and then click Confirm.
Select your router's 2.4GHz host network and enter the password,
Connect the Extender to the Internet