What means a point after new class()

class Context {   

  public string FirstName { get; set; } 

    public string LastName { get; set; }

     public string Sex { get; set; }   

  public string Address { get; set; } 

}  

class Customer {     

private Context _context = new Context(); // Initializes the context     

 // set the value for properties    

 public Customer FirstName(string firstName)  

   {         _context.FirstName = firstName;   

      return this;     }    

  public Customer LastName(string lastName)  

   {         _context.LastName = lastName;   

      return this;     }   

   public Customer Sex(string sex)     {  

       _context.Sex = sex;      

   return this;     }     

 public Customer Address(string address)   

  {         _context.Address = address;

         return this;     }  

    // Prints the data to console 

    public void Print()     {    

     Console.WriteLine("First name: {0} \nLast name: {1} \nSex: {2} \nAddress: {3}", _context.FirstName, _context.LastName, _context.Sex, _context.Address);     }

 }  

class Program {    

 static void Main(string[] args) 

    {         // Object creation     

    Customer c1 = new Customer();  

       // Using the method chaining to assign & print data with a single line  

       c1.FirstName("vinod").LastName("srivastav").Sex("male").Address("bangalore").Print();     } 

}