Can someone explain what I need to do in order to import a custom portrait and create a custom character model?

From what I've read so far, a custom portrait can be imported and associated to a character model with a Mod Editor tool or something? Is that tool something that comes with the game and I just need to find the right exe in the file directory or do I need to download that independently?

I thought I saw a video where they said you could mix and match existing assets and change part colors to make new character models, but it wasn't clear if that was a steam workshop exclusive, a tool that shipped with the game (like in Neverwinter Nights 2), or some 3rd party tool that I haven't been able to find.

Then the portrait and character model are baked together, the resulting files are placed somewhere so the game can pick them up and are useable right?

Can someone set me straight here on how this all works?

For the portraits:

There are two ways to do it:

1. with a resource extractor / injector, you'll find one on Nexus.

2. Creating a mod, which I find the more elegant solution.
Check the mods on Nexusmod, see how these guys do it.
They sometimes have different portraits / images available for one character, meaning that they are available as files. Give the file the right name and it will replace the image in the game.

I took one of these mods, then photoshoped one of the chars to my liking.

NVM this post wrong thread o.O

But with the mod tools (as i posted in a new thread) there should be a sample mod for this kind of stuff

Hey, everyone!
Can I buy JA 3 on GOG and then use steam workshop mods? Is there a way do so? Yeah, I know, there's Nexus mods, but what if there won't be mods I need available on Nexus? Or it will be outdated.