4-horse harness: help me fill in the blanks to build this?

Credit to Mitah Val Karem for the best four-horse team MOC I've seen. Anything else I've come across looks clunky and hard to steer. I'm trying to re-create this harness for my own team, but I'm struggling to figure out how things connect together and I can't find instructions anywhere, unfortunately. This is what I have so far: Part ID Qty Placement Brick 1x1 w/ 1 knob 87087 2/horse Where horse saddle would normally be, knobs pointing to the sides Plate 1x1 w/ upright holder 44842...