When I first started learning about unity, I liked to create some simple games by myself. When I created a game, I had no choice but to use scenarios and characters or models.
In the early stages of learning, I tested the corresponding folders under others' engineering files to my asset directory, so that the assets will be loaded when unity starts, and then loaded into the scene, if these models appear independently and are not dependent on other resources, it is easy to do so. If the asset you use depends on other model files, materials, textures, animations, sounds, and so on, this will affect you, another point is that you may find that you have spent a lot of time creating these relationships and that the models are different from those in other projects. For example, if you want to put AI in your project, you will be exhausted.
In fact, unity has helped us.Export Function, You can easily retain these relationships and replace all dependent assets for you.Export.
Method:
Right-click the asset you want to export, for example, a prefab. Right-click the export in the menu and select import custom package in your project.