DISCLAIMER 1: I have not had a 100% success rate with this part, as one of my skins caused my game to crash although it may have been something else, if you see any issue issues with Part.2 Please correct me!

DISCLAIMER 2: This is for those that have already read through my tutorial and that are ready for this part. You need to have descr_model_battle.txt, and feral_export_descr_unit.txt setup.

Also a link to the mod/part 1
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2474943240&searchtext=

This is needed to start, unless you already have a unit setup!

Tools and links:
INTEGRATED WORLD TERRAIN EDITOR and Battle Model Editor
By: " wilddog"

https://www.twcenter.net/forums/downloads.php?do=file&id=2741 Download Link

For: Has a variety of functions and is probably one of the most helpful tools when modding RTW. There are a variety of functions included that I have not tried, but the two most important are the conversion of textures for use, as well as model conversion from .cas to dae (usable in blender)

Paint.NET
https://www.getpaint.net/download.html
For: It is my go-to for texture editing, although any texture editor can work really.

Steps:

For this example I will be choosing to edit/add an Iberian Infantry to Scipii (Why? I dont know).

1.) Find the texture you wish to edit by going to Rome Total War: Remastered, Right click it, and find "Browse Local Files", then proceed through Contents -> Resources -> Data -> data -> characters -> textures (Hooray you found it ːbad_beautyː ).

2.) Look for the texture you wish to make edits to, then copy it to your mods folder.

if you are having troubles finding the textures for your unit, open up "feral_export_descr_unit.txt" , hit "Ctrl + F" and search for your units name. After finding your unit, look for the line that says "soldier". The name after that is your units model, use this to find the texture by opening "descr_model_battle.txt" and again hitting "Ctrl + F" then paste in the name of your units SOLDIER MODEL (again its the name after "soldier" in descr_model_battle).

(IMPORTANT) It must have the same folder structure as Vanilla!
Ex: mymod -> data -> characters -> textures

3.) Assuming you have been a good little boy/girl and you downloaded the tools like I told you (if not, shame on you ːGuardsmanː ) then run the IWTE_launch.bat from the "IWTE_v21_05_A" folder that you HOPEFULLY extracted from the zip.

4.) Now we need to convert the textures that are currently unusable because they are compressed, to do so go to the "Rome Remastered" tab on the top bar, and find the folder with the texutures you wish to convert. you can choose to convert the directory you setup (the textures folder in your mod folder) or you can convert every texture in the game by just selecting the orignal "textures" folder. Either way after you find and convert your texture into a usable form, it can be found in your "IWTE_v21_05_A" Folder, under "textures" (It may be different for you).

5.) Copy the converted texture back to your already existing texture and replace it. Now it is usable for editing.

6.) Make your edits, then make sure to save it as a .DDS with the Bc3 (Linear,DXT5) Setting.

7.) The texture it ready, and now its time to make it used by the game.Go back to your "descr_model_battle.txt" and find your unit. Then , copy and paste one of the lines with a faction name under another. Then change the name from whatever it was before to YOUR factions name. Then change the texture to..well your texture. Ex:

texture data/characters/textures/carthaginian_cavalry_carthage.tga
texture slave, data/characters/textures/carthaginian_cavalry_slave.tga
texture spain, data/characters/textures/carthaginian_cavalry_spain.tga

to

texture data/characters/textures/carthaginian_cavalry_carthage.tga
texture slave, data/characters/textures/carthaginian_cavalry_slave.tga
texture spain, data/characters/textures/carthaginian_cavalry_spain.tga
texture romans_scipii, data/characters/textures/carthaginian_cavalry_scipii

(the file extension doesn't matter, I think feral just messed up the conversion and left the .tga inside the names)

and that's it!

if you had any troubles, leave a message! Also please up vote the mod, it takes some work setting this up and I really appreciate the up votes! ːsteamthumbsupː