Can't set up tvheadend server

I just installed Kodi on a Pi4. I intend to use it as a backend for a QuadHD usb tuner.

I was under the impression Tvheadend is pre-installed. However, when I tried to follow the directions on Tvheadend - Official Kodi Wiki to configure it with the web server I get a can't connect error from Firefox. I know the Pi is connected to the network because I can connect to it with SSH. I confirmed I have the correct internal IP for the Pi and the correct port. I found several posts about similar problems, but none of the suggestions worked I read one post that said it was installed, but not activated. However, I didn't find the activation setting where he said it would be. I'm a newbie to both Kodi and Linux, so please keep instructions simple.MORE INFORMATION! I just noticed an error poping up while the add-ons load. It said "communications error, can't connect to Tvheadend". since the error didn't specify if the problem was with the server or client, I uninstalled the client. that error wend away, but I now get 2 others."communications error Tvheadend HTSP client inactive or not installed. I checked the logs and the contained nothing. strange, since I've also been getting an error saying "forum browser, check the log for more information" The pi was connected to a wired ethernet connection with internet when I got these comm errors.

I searched and searched, but failed to find that! Thanks! What are the nightly builds? are they stable?

Problem solved! Thanks erbas! I was relying on an apparently out of date website info that said tvheadend was pre-installed in Librelec after searching for it in add-ons but failing to find it. erbas told me where to find it. I'm logged into the configuration right now.