Hi everyone,
A little Background on me:
I'm Fairly New to the game and the final fantasy world. The FF game I played was Final Fantasy X and x-2. I come from WOW (vanilla through Wrath of Lich King days and DCUO)
So my MMO experience isn't that bad. I love playing Healer classes. My questions are as follows.

Leveling:
  • Can I/or Should I Level My Class to level 50 and than level a second class to 15 to get a job(currently CNJ)
  • If i level my Job to 50 and switch to my level 15 class will it auto level to 50?
    Or should I just Level on class to 30, than another to 15, than my job to 50?

Overall I am very confused on the leveling and how to go about leveling correctly and efficiently. I know what class and jobs I might be interested in I just want to make sure I level them to benefit my group play as much as possible. Any Help would be appreciated thanks again!