I want to add one more NIC to my Orange Pi PC with OpenWRT 18.06
dmesg tells:
[45.521359] usb 7-1: new full-speed USB device number 2 using ohci-platform
[45.790384] usb 7-1: New USB device found, idVendor=0fe6, idProduct=9700
[45.797106] usb 7-1: New USB device strings: Mfr=0, Product=2, SerialNumber=0
[45.804646] usb 7-1: Product: USB 2.0 10/100M Ethernet Adaptor
The page you linked is about tethering to a cell phone. Is that what you're looking to do, or to plug in a USB Ethernet dongle?
Many of the package lists, especially on the old wiki (current is http://openwrt.org/), are outdated. Installing the "main" package or packages (or adding to a build) should automatically add the appropriate dependencies.