If the Connection is DSL, make the model as bridge method and configure it.
Highly recommended is the directly terminated from tower advise to put 4-port or 2-port switch before firewall wan connection

Step 1: Login to the Tacitine. (If you are configuring the Tacitine for the first time, the default Lan IP is https://192.168.100.1)and Default username: admin & Password: admin99

Step 2: Click the Network Setting tab.

Step 3: Click WAN1 for the WAN interface (WAN1 by default.)
Step 4: In Wan connection method > select PPPoE and mention the username and password provided by ISP

How to configure wan in PPPoE

Troubleshoot

Step 1: Click the Status > System Command >Ping

Step 2: Ping your ISP’s Default Gateway or any IP that is pingable on the Internet (e.g. 4.2.2.2).

Step 3: Also try to ping a website (e.g.: google.com) to ensure that the DNS resolution is working.