headend

[TheDreadPirate]

You both need to install the TVHeadend plugin AND setup the TVHeadend server. Jellyfin does not natively support Hauppauge tuners and requires either TVHeadend or NextPVR to run separate from Jellyfin. The plugins you install in Jellyfin allow Jellyfin to then interface with TVHeadend or NextPVR.

Each app have setup guides on their respective sites. Once you've setup the apps, the Jellyfin part is fairly simple.