need help making minecraft quest villager

im using chat gbt and i asked him "make minecraft quest villager named "librarian" ha has 5 slot quest can be done for free and after you done 10 of them you lvl up max lvl of "librarian" is 10 lvls max make it for every player separately when you lvl up "librarian" he will give quests lvl 2 whice gives you better rewards and diferent quests to do can you explain me how to do it step by step in datapack?" but i dont want to mess up chat gbt cannot see my working proggres and mistakes i do so i will need your help