Is there anything else that is needed when setting up the IP Phone?

Or it is enough to put IP-Phone on specific LAN(Advanced > Network > IPTV/VLAN > Custom)

Router: TP Link AC1200 C6

Phone: Axtel AX400G

ISP: Telekom (Germany) Fiber Optic

Because I'm trying to follow the instructions on the Axtel website, and I cannot seem to get the IP if I connect it to an IP-Phone LAN.

But if I connect it to other ports that isn't IP-Phone (e.g. Internet, IPTV), I can get it but nothing is happening when I try to set it up.

Thanks!