This was converted from Civ 5. You can see how the converted Civ 5 animations are hooked up in Ballista.ast. I replaced the original human operators with models made by combining different Civ 6 meshes.
To see how the flaming arrow attack was made by looking at ATTACK_A under m_Timelines as well as FX_Ballista_Fire_Trail.ast and FX_Ballista_Arrow_Trail.ast for the rescaled visual FX.
A custom mesh for the helmet, MacedonHelm_A.ast. Several reskins of the Hoplite shield (the MacedonShield_*.ast files). Macedon_ArmorA.ast and Macedon_Sarissa.ast are just reskins.
This is just a reskin of the Quadrireme but uses the Metalness and Gloss to make the golden eagle emblem look metallic and shiny.
This was all just made from base game parts apart from a reskin of the Mamluk armor to make more of it recolour-able using Tints.
Even Moar Units! Macedon and Persia (Modbuddy Project) 1.0
Graphics for Ballista, Pezhetairos, Cataphract and Royal Warship