You have to talk to Kreia about it on the Ebon Hawk. If I remember right, you tell her that you're ready to learn more about the force, and she asks you what field of jedihood you want to pursue. You tell her, and that's it. No tests to see if this field is compatobile with your personality, no hoops to jump through, you are what you are, and that's it.
zefie is right, as i usually get the prestige class on my first planet after telos, and i always do the secret tomb near the end. the only requirements are to be aligned strongly to either ds or ls, be at level 15 or more, and talk to kreia.
guess its too late for me, saved koriban for last, and i cant talk to kreia to get the prestiege class conversation... just locked in on tellin me to go to dantoonie to the enclave
