Im really lost :(

[FallenBracho]

oh god, why the site of final fantasy is so confusing? it does not speak any of that, I played ragnarok for 8 years and the site was so explanatory, I will have to make a new char T.T

[Niwashi]

I will have to make a new char T.T

No you don't. Just add Thaumaturge and Archer as additional classes along with Conjurer. This game allows you to advance any or all of the classes.

1st: Reach level 10 in your initial class and do the level 10 class quest. This unlocks the ability to add other classes.
2nd: Go to the class guild for the class(es) you want to add and do the introductory "So you want to be a <class name>" quest. This unlocks the new class and gives you a starting weapon or tool.
3rd: Once other classes are unlocked, you can switch between them whenever you like just by changing your main hand weapon/tool.

Note: Your level is specific to a particular class, so if you're a level 10 CNJ when you unlock ARC, switching between a wand and a bow will switch you between a level 10 CNJ and a level 1 ARC. You'll need to level up each class independently (although you do get a 50% bonus to XP when on a class that's lower level than your highest one).

[Umo]

oh god, why the site of final fantasy is so confusing? it does not speak any of that

Yes, it does. More or less... At least for paladin, black mage and white mage

FINAL FANTASY x|v > ARMOURY > JOBS

By achieving sufficient mastery in a certain class, adventurers will be able to begin undertaking the mantle of a related job. For instance, gladiators may rise up as paladins, stout swordsmen who shield comrades from harm; thaumaturges may aspire to become black mages, masters of offensive magic; while conjurers may find a new calling as white mages, masters of healing.

PS. I do agree, the site does not offer proper/enough information on this. My nitpicking post is just to encourage you to read as much as you can in-game, active help windows and quests especially. Also, stick yourself to the main story quests and don't forget to go back to the guildmaster of your current class every 5 levels (5, 10, 15,...)