Well, Planeshift doesn\'t use classes. You don\'t need to pick a class or something. You can just train the skills you like to master. At this moment only a few skills are implemented, as the PS is still a game in his very early stage of developement (pre-alpha tech demo).
Skills that are implemented are: fighting skills, magical skills and mining skills. Basic crafting skills might be implemented soon. (don\'t ask when, it\'s unknown

)
Feel free to roleplay whatever \'class\' you like, be it a ranger, cleric or something else. Nobody will ask if you can back it up with skills.
Have fun!
Edit: I assume you know how the training system itself woks, as that is handeled in your previous thread.