Ecowitt's app (WS View) can add the Ecowitt Gateway in pretty easily and it adds it to the WiFi during that process (like most home WiFi devices now).
From there I use my drivers (there are a couple choices so I will just link to the community drivers page). Not sure why mine do not get more hits through here since they are fairly popular but whatever. 
There are instructions in my driver (I think the other ones also) but it basically involves setting the Ecowitt to send the data to a custom location (your Hubitat's IP) with a specific port # so the Hubitat recognizes it. Then creating a virtual device on the Hubitat with your Ecowitt's MAC address the DNI (lowecase, no : or spaces in it, for example AB:CD:EF:01:23:45 would become abcdef012345 as the DNI). From then on if the Hubitat gets anything from that MAC on the port it will send it to that device's driver to handle.