I wanted to make a class diagram following the instructions from this post for C# using Visual Studio:
https://stackoverflow.com/questions/17191218/generate-a-class-diagram-from-visual-studio
I am stuck at this instruction:
“1. Right-click on the project and select Add → Add New Item. A. Search for ‘class’ word and NOW you can see the Class Diagram component.”
I googled and I assume I should be finding a project file in the Solution Explorer. However, it does not exist on my side.

What should I do to create the project file for all the Unity scripts?