hello all this is my first FF MMO game i have ever played, so in a way i am very confused.

my only real concern is, how i become a black mage, my THAUM is level 11, people said oh you just equipped a bow and level as a archer to level 15... and then switch to THAUM and level that to 30 and you get a soul gem... but how do i switch to archer.. i am so confused with this, if their is a in depth guide that explains all of this that would be so nice.

thank you