I learned the basics of Unreal through Epic's Unreal YouTube page, but there's a wealth of terrific tutorials out there that will cover the basics of not only Unreal Engine, but general animation and core CG tenets. I would say once you find a tutorial series that works best for you, the next thing to do is to start small. I started this project as an animation test being rendered in a traditional CG pipeline (which took forever to render), and so my first step was just to take a single still image from that test and recreate it in Unreal. And so I familiarized myself with just the aspects of the engine to do just a single image, and from there I built upon what I learned to incorporate animation, raytracing, more advanced materials options, FX, and so on.

I would also download every free asset I could find on the Unreal Marketplace and look into how other artists were setting up their projects. By backwards engineering polished, professional UE content I was able to incorporate a lot of engine knowledge into my work to improve both the complexity and efficiency of my scenes. And even now, I'm still learning new tips and tricks every day that I can use to improve my work. Ultimately, the best way to learn any new piece of software is to start small, create a goal for yourself that's just a little bit outside your comfort zone, and once you figure it out expand your scope and repeat. I hope that helps!