Hi! Thank you very much for supporting my work!
I'm not familiar with Unreal Engine. I think it's a good idea to watch a tutorial for that, or see the engine's documentation.
Some of the formats included come with the texture and material data packed into the models, but you might have to tick some boxes in the engine upon importing the stuff.
If you'll get stuck, please let me know, so I'll ask the game devs in my Discord community server. Some of them are using Unreal Engine, they might be able to help!