First you need to know your Unifi pppoe user and password. Then follow the steps below

Go to Dial-up and setup new connection






Choose Broadband (PPPOE)


Login your router, go to the WAN settings in your router. Then copy your PPPOE username and password into here.


Now you can unplug your router, then connect the Unifi modem (BTU) directly to your PC. Then click "Connect".