How to use a variable value as the name of a class in c#?

I am trying to create some sort of test console application where I will be able to apply at least some of the code into a real application. I want the user to be able to create employees indefinitely with unique names. Because of this requirement, I want the name of the class that I am creating to be the name of the employee. I have a variable where I have collected the name of the employee but I can't make it so that the name of the class is equal to the value of the variable. I understand it is very crude code but I just want help with this issue.

I tried using the variable name but it obviously threw an error. I checked the internet as well but I could not find anything that could help. Here is my code so far:

using System;
public class Employee
{
public string firstName;
public string lastName;
public string emailAddress;
public int age;
public Employee(string name1, string name2, string email, int age1)
{
firstName = name1;
lastName = name2;
emailAddress = email;
age = age1;
}
public void ListEmployeeDetails()
{
Console.WriteLine("--Employee details--");
Console.WriteLine("~~~~~~~~~~~~~~~~~~~~");
Console.WriteLine($"Name: {firstName} {lastName}");
Console.WriteLine($"Email: {emailAddress}");
Console.WriteLine($"Age: {age}");
}
}
public class Program
{
public static void Main(string[] args)
{
// Setup
string decision;
string firstName;
string lastName;
string emailAddress;
int age;
bool next = true;
Random rnd = new Random();
int num = rnd.Next(1, 201);
// Explanation
Console.WriteLine("Welcome to Employee console simulator. \nWould you like to create a new employee, remove an employee, or check an employee's work hours?\nPress 'a' to create new employee, 'b' to remove an employee, and 'c' to check an employee's work hours.\nPress 'e' to exit.");
while (next == true)
{
decision = Console.ReadLine().ToUpper();
switch (decision)
{
case "A":
// Create new employee
Console.WriteLine("Enter new employee's first name:");
firstName = Console.ReadLine();
Console.WriteLine("Enter new employee's last name:");
lastName = Console.ReadLine();
Console.WriteLine("Enter new employee's email address:");
emailAddress = Console.ReadLine();
Console.WriteLine("Enter new employee's age:");
age = Convert.ToInt32(Console.ReadLine());
Employee **{firstName + lastName}** = new Employee(firstName, lastName, emailAddress, age);
break;
case "B":
break;
case "C":
break;
case "E":
break;
default:
Console.WriteLine("That is not a valid command. Please enter again.");
break;
}
}
}
}

It seems that you need to get acquainted with collections in .NET. In this case dictionary (Dictionary<string, Employee>) seems to be a good candidate:

var employees = new Dictionary<string, Employee>();
while (next == true)
{
decision = Console.ReadLine().ToUpper();
switch (decision)
{
case "A":
var fullName = firstName + lastName;
if (employees.ContainsKey(fullName)) // check if user already is present
{
// TODO
}
else
{
// if not - add new one
employees.Add(fullName, new Employee ..);
}
break;
// ...
}
}