Help one physical network port connects to rtl8367s phy switch to configure the VLAN

I use a physical network port to connect to the PHY SWITCH through GMAC, and I want to set it to WAN and LAN separation, please help me see how to configure it .thanks

This is the physical design on most devices supported by OpenWrt, just follow the examples of other devices (including rtl8367s ones); bonus points for using DSA.