It took me days to figure it out and I still don't have it 100%
the badge templates last I knew dont really work properly so you have to sort of work around it. lots of little things to make sure you do right (image size, make sure its in multiples of 64), make sure you select color if you want it to have color (things I messed up before).

the 3d modeling part isnt an issue with badges as they are really just 2d with a little depth which is added by substance.

I forget how I do it every time until I really dig in (which is why I don't update my mods a ton), but the guides for the most part are still okay, at least getting you started, its the new unreal engine that not updated. Wish I could be more help but I am not the person to put together a guide as I don't do it the "proper way" haha.