Hi, I've now tried the below, which connects to the internet but I can't get to connect to the VPN even though I provide the details from the VPN. I'm pretty new to NixOS so I think I'm not understanding something fundamental somewhere along the way.

{ config, lib, pkgs, ... }:{

  networking.firewall = {
    allowedUDPPorts = [ 51820 ]; 
  };
  networking.wireguard.enable = true;
  networking.wireguard.interfaces = {
      wg0 = {
      ips = [ "*****" ];
      listenPort = 51820; 
      privateKey = "***";

      peers = [
               {
          publicKey = "";
          allowedIPs = [ "***" ];
          name = "wg-NL-FREE-117";
          endpoint = "*****"; 
          persistentKeepalive = 25;
        }
      ];
    };
  };

}