@Lokahi89 Connect your computer to your ont to make sure it works. If it does, connect the TP-Link device back. Log into the TP-Link router and go to the status page, you should have an IP address. If not, the ont is not giving a internet connection to the router, try rebooting the router to see if that works. If you do have an IP address in your Internet section or WAN, you may need to configure DNS servers.

This FAQ will show you how: https://www.tp-link.com/us/faq-1712.html