How C# program executes

When you select “Build Solution” from the Build menu, the IDE
compiles your program. It does this by running the compiler, which
is a tool that reads your program’s source code and turns it into an
executable. The executable is a file on your disk that ends in .exe—
that’s what you double-click on to run your program. When you build
the program, it creates the executable inside the bin folder, which is
inside the project folder. When you publish your solution, it copies
the executable (and any other files necessary) into the folder you’re
publishing to.