I've been reeding a book which was about C# programming language and faced the term set, So now my question is what the word 'set' came in the following means?

Pattern matching with the switch statement: Like the if statement, the switch statement > supports pattern matching in C# 7.0 and later. The case values no longer need to be literal values; they can be patterns. Let's see an example of pattern matching with the switch statement using a folder path. If you are using macOS, then swap the commented statement that sets the path variable and replace my username with your user folder name:

1. Add the following statement to the top of the file to import types for working with input/output: using System.IO;
2. Add statements to the end of the Main method to declare a string path to a file, open it as either a readonly or writeable stream, and then show a message based on what type and capabilities the stream has, as shown in the following code:

  // string path ="/Users/markjprice/Code/Chapter03"; 
  string path => @"C:\Code\Chapter03"; 
  Write("Press R for readonly or W for write: ");
  ConsoleKeyInfo key = ReadKey(); 
  WriteLine(); ...

actually my question is about the following part:

If you are using macOS, then swap the commented statement that sets the path variable and replace my username with your user folder name

Would anybody exactly explain it to me?