upper hinge: the bolt goes into the hinge from the inside of the door opening into a caged nut.
lower hinge: the bolt goes into the hinge from the front side of the door hing pillar, caged nut or just a regular nut there.
see the assembly manual, section 1 sheet 59 for the details
https://www.trifive.com/d1/55-59Assy.pdf