Successfull logged in with facebook, now what?

So I have managed to log in with facebook and i have the id_token but now what?
Before this I have played with okta default auth server and that worked too, i have managed to get the code and exchanged it for an access_token and id_token and used the access_token to retrieve the user info from oktas server. I haven’t done anything with the id_token (honestly i don’t even know why this exists in the first place, if someone can enlighten me on this part it will be much appreciated).

But after I have logged in with FB, i got the id_token and when i decoded it, nothing useful.
Is this token meant to hit the facebook endpoints to retrieve the user info?
Not sure how it works.