I just went thru this, so will try to explain what I did, using available pics from you and Rudy, since I can't find mine.
1st Pic. Arrows show the hooks/rods that go up to the catches at the top and bottom of the doors. When the handle is rotated (down) from the neutral position (should be horizontal facing inward), the latch (item B in 2nd pic) rotates and pulls the rods/catch plungers down, to release the catches so the door can open.
2nd Pic: Item A should hook into the latch plate (item B), but also needs an additional piece (see pic 4 below) . Item C in this pic does not go there - it is used to connect the rod (A) to the catch (item C in the next pic). Need one for both upper and lower.
Note my nomenclature here: I use the word 'catch' for the upper and lower release plunger mechanisms in the door, and I use 'latch' for the plate that rotates and pulls the rods when you flip the handle.
Pic 3: This shows one of the (2) catches that go at the top and bottom of the door (mine were pretty rough, I cleaned them up a lot). The clip (C) is used to attach the rod to the catch. I think the purpose of this is a) for assembly and disassembly, and b) to allow for some motion between the rod and catch.
Pic 4: Shown here are the 2 pieces that go from the rod (A) to connect to the latch plate (item B in above pics). These allow for the adjustment of the rod/catch so that the upper and lower catches are well latched when the door is closed, and release when you flip the lever. These adjustment pieces hook into the holes in the latch plate (item B above). Note the position of the flip lever.
Pic 5: This shows the catch and little clips (snaps) that connect the upper and lower rods to the upper and lower catch assys.
The trick: once you get these pieces basically in place, you need to position the latch plate (item B above) such that hooks into the rods and sits in a neutral position with the flip lever in the correct horizontal orientation, and the plungers on the catches sitting out so they catch in the catch plates on the sill and header. Then, when you push the flip lever down, the latch plate rotates and pulls the rods down, which in turn pull down the catch plungers and let the door open.
Once you line up the hole in the square peg that the flip handle fits on - along with the holes for the little pin that holds the handle to the peg (I used blue locktite), then the correct orientation of the catch plate to hook into the rods should be more obvious (even to the most casual observer.

). It takes some playing with. I had the door sitting flat on a couple of saw horses so I could sit there and noodle on it forever. My assembly came to me all apart, which made for a lot of fun. Took me a while to figure it out. And, if you re-tap the holes for securing the upper and lower 'catches' to the doors, they are 5mm and not 6mm
Hope this helps some and doesn't further confuse.