Whether you are just starting to learn Unreal Engine or are interested in some are that you have no experience of, then we recommend the Example Content project that Epic Games has provided for your benefit. You can find it through Epic Launcher, under the Learn tab in Unreal Engine section.
It contains numerous examples from all areas of game development. They are divided on separate maps for each subject. If you meticulously go through them, you should have quite good basic level understanding about
- how to import models,
- how to make materials,
- how to make effects (there are even Niagara examples),
- how to animate characters,
- how to use physics,
- how to make game environment,
- how to implement game mechanics and interactions with Blueprints
and various other subjects. Even if you are experienced game developer with some other engine, it is worthwhile to skim through this, since it shows you how things are done in Unreal Engine.
Unreal Engine Pathways 