Unlike Destiny 2‘s beta, players need to unlock the other subclass. This is something that will come with time, but that amount of time will differ based off how you play. You could easily finish the story or even the raid without figuring it out, assuming you have bad luck/don’t do certain tasks. To avoid this fate, here is how you unlock the other subclasses.
When opening chests and other activities, there is a chance an item will drop that unlocks the subclass. After that, just keep killing enemies and it will eventually open up a quest.
Finish the Quest
Finding the quest is far from difficult, with it having its own location, icon and even stating that it is the subclass quest. As for the quest itself, it’s just involves killing enemies and then touching a shard of the traveler.
Fans of the subclass events in the original will be delighted to know there is a section after unlocking the subclass where you can use abilities excessively. Upon defeating all the enemies the quest will end and the subclass will be unlocked.