This sort of question seems to be a theme lately. Fallout / wasteland are HUGE games, made by a large team of artists and programmers with decades of experience between them. There are no ‘make a AAA game’ tutorials.
Fortunately, there are loads of good tutorials on 3D asset creation, blueprints, level design and lighting, and so on.
Why not pick something you are interested in, and make a mini-game to showcase that new skill? Could be Art, gameplay, a new game mechanic, or a particle effect. A simple game or environment is still a ton of work, and you’ll know how much you can manage in your own.