I remember it was several years ago when I first came into contact with unity3d, when I had to work on a project and time was tight. I remember learning it in about a month. I think it's better to use c-sharp and js, or js. At that time, the project was an Internet of things system, which needed to show the location of the characters on the 3D floor. The 3D floor was relatively simple, but the more complex was the hardware interaction. The front end only needed to be displayed.
the general learning route should be to understand the principles of 3D, such as perspective, camera and other 3D world, and what concepts are involved at the computer language level, and then learn how to implement functions in the unity3d framework, such as the life cycle of the program, how to get 3D objects, how to manipulate them, and so on. It is not recommended to start with packaged libraries such as game engines. At first, they should be based on basics. when the concepts are almost understood and the basic programs can be written, it will be easier to get started with the game engine.