Well, since I just can't think straight at the moment it's pretty hard for me to figure out how to click by slot.
inventory.interact(ctx.inventory.getSlot(arg0);Doesn't work. (Which is no surprise)
Any other way? I need to click the first 4 items in inventory. However the interact method is too slow for me. That's why I'm trying just to click the slot instead of the item itself.