WD15 dock incompatible with Arch Linux laptop

I've got a WD15 dock and a Dell laptop running Arch Linux. I inserted two monitors' HDMI plugs into the dock and plugged the dock's USB-C cable into my laptop. The laptop display outputs correctly to the monitors. I inserted the plug of a USB keyboard and mouse into the dock, but the laptop didn't detect them. I plugged an Ethernet cable into the dock, but the laptop did not detect that either. What must I do to make the laptop detect the keyboard, mouse and Ethernet cable that are plugged into the WD15?