First port of call: find a video that teaches you the UI. Don’t start watching videos that assume you’re already familiar with the editor until you have got to grips with the interface. There are plenty out there, just make sure you learn the terminology and where things are first before you jump in to making something. Less annoying that way.
My personal recommendation would be to focus on one thing at a time, don’t try to learn 3 things at once. If you jump from one thing to another then you will encounter frustration and possibly become discouraged, as every time you start to make progress in one area and things begin to click, you’ll jump to something new and suddenly you’re back to square one. It can also become easy to start forgetting the stuff you’ve just learned because you’ve not given it time to properly sink in.
I recommend you try a few things, find one you enjoy and stick with it until you feel you understand it well. It could be level making, modelling, blueprints, C++ code or creating materials, but try to focus your attention where possible. Don’t aim to be a master at everything, as few people are truly all-rounders. Most people have certain areas they excel in, and then they learn other skills for variety or to fill knowledge gaps if they’re working alone or in a small team. Of course, there’s no limit to what you can learn, so over time you can develop a deep and broad knowledge of game development, but don’t try to do it all in one go 
