From Stornway, head east and then north. You'll eventually reach a mountainous region. Your destination is the Tower of Trades, a prominent structure. The monsters on the way to the Tower of Trades will be even stronger, so ensure your party is at a good level (around level 10-12 is recommended). The Tower of Trades itself is a multi-floor dungeon filled with new and tougher enemies. Navigate its winding paths, solving simple environmental puzzles and collecting treasure. The tower's design can be a bit confusing, so pay attention to your map.
At the top of the Tower of Trades, you'll encounter a significant event that leads to the unlocking of Alltrades Abbey. After a series of cutscenes and interactions, you'll gain access to this sacred place. Alltrades Abbey is not a town but a special location where you can change the vocation of any of your party members. This is a game-changing mechanic, allowing you to customize your party's roles and abilities. Experiment with different class combinations to find what suits your playstyle. Remember that changing vocations resets a character's level to 1 for that new class, but they retain all learned spells and abilities from previous vocations, making multi-classing very powerful in the long run.