Right now, I'm learning how to import textures into the mod, and after reading this thread, I've just realized how ancient the Creation Engine is.
https://forums.unrealengine.com/t/what-image-format-do-i-need-and-how-do-i-implement-it/287448
Here's a quick tutorial.
I'm using Unreal Editor 5, but I probably should be using version 4. I don't know if there are significant differences between the two, so I'm going to assume that the menu layouts are the same.