After watching many GT builds I realized many of them don’t have the passive skills put there, what I’m unsure of if there is another way of casting them once somehow from somewhere else or just everyone put it in the skill bar then remove it, obviously when you don’t have enough space for all the skills.
You get 2 skill bars that you can swap using whatever hotkey you have set it to, or by clicking on the little arrows right next to the inventory/character button.
Usually people like to put all their passives on one skill bar and their active skills on the other.