I'm not an expert too but I try to help other users with what I know based on my own experience. Your tv should have a facebook app in the dashboard. After you click the app card/icon, you'll have a series of instructions on what to do before you can access your facebook account in the tv completely. Better yet, you can also watch this video:
I'm sorry if my question is not very challenging but I thought that I can get an answer here immediately since you are experts. My smart tv is from lg which was released earlier this year.