There is a alpha client and instructions available here: https://smartdigihere.com/jellyfin-on-samsung-smart-tv/

However as stated further down the article, it's easier to just use a web browser and access your jellyfin server that way. Login, bookmark the URL (don't forget to include the port) and then hit full screen.

Note: You may need to tweak (server side) your transcoding and subtitle settings.