How do i get a job advancement for my magician on Maplestory?

Can anyone tell me how to get a job advancement for my magician? And tell me the proccess or something like that? And maybe what order they come in?|||first, go to grendal the really old. he would give you a letter and would tell you to talk to the job instructor. go to the portal that is near the middle of ellinia. after you get into the portal, go one more screen to the left. you should be able to see a big fat cat. go to the very top of the map and talk to the instructor. he would transport you inside the tree and would tell you to collect 30 black marbles. there are horny mush and cursed eyes in there. they are modified. the horny mush is stronger (takes about 2 magic claws) and cursed eyes take about 2 magic claws too. they drop marbles and it isnt really hard. you would need a lot of hp and mp pots because if you leave the tree, you would have to give the instructor the marbles you have and hunt 30 more. after you finish the 30 marbles, go to the instructor (hes now in the tree) and he will give you a proof of the hero. head back to grendal the really old and you can choose which mage you would want to be.