How would i enable the sytem service for my wifi dongle driver?

I found that my realtek dongle’s driver is in the nixos repos and, after installing it using the config.nix, have no idea how to enable it. i’ve tried using systemctl but that has not worked.

Here is the driver for reference: NixOS Search

i’m brand new to nixos so this is all very confusing, but im willing to learn! Thank you and have a great day/night!

This should work after switch & reboot (if you picked the driver correctly):
boot.extraModulePackages = with config.boot.kernelPackages; [ rtl88x2bu ];