fitpc2i not detecting second network card

[philip52676]

Hello, I have a FitPC2i with 2 gigabit network and 2GB memory and Wifi. during the installation of the opnsense firewall, it only detects 1 gigabit network as my LAN and the Wifi as my WAN. how come it didn't detect the other 1 builtin network card of my FitPC2i? My FitPC2i network card specs is 2gigabit Realtek RTL8111F-CG GbE controller. Wireless is WLAN 802.11 b/g/n (2.4GHz Qcom LR802UKN2 module).

fit-PC2i-C1600-D2G-W is the hardware I'm installing the opnsense firewall.