Trying to add data to my List<book> but getting "No overload for method takes 2 arguements". What can I do?

You want to add a Book to your List<Book>... but you're not actually creating a Book instance. You probably want:

Book book = new Book(bookTitle, bookAuthor);
books.Add(book);

... that's after you've changed the name of your List<Book> variable to books, too. It should almost certainly be an instance variable, too. Additionally, I'd stop declaring variables at the start of your method - declare them where you need them. For example:

private readonly List<Book> books = new List<Book>();

public void AddBooks()
{
    Console.WriteLine("How many books would you like to add?");
    int count = int.Parse(Console.ReadLine());

    // Note change from <= to <
    for(int x = 0; x < count; x++)
    {
        Console.WriteLine("Enter Title.");
        string title = Console.ReadLine();

        Console.WriteLine("Enter Author.");
        string author = Console.ReadLine();

        books.Add(new Book(title, author));
    }
}

You might also want to separate the "asking how many books to add" from the "adding a book" part:

private readonly List<Book> books = new List<Book>();

public void AddMultipleBooks()
{
    Console.WriteLine("How many books would you like to add?");
    int count = int.Parse(Console.ReadLine());

    for(int x = 0; x < count; x++)
    {
        AddBook();
    }
 }

 public void AddBook()
 {
    Console.WriteLine("Enter Title.");
    string title = Console.ReadLine();

    Console.WriteLine("Enter Author.");
    string author = Console.ReadLine();

    books.Add(new Book(title, author));
}

Then consider whether the user input should really be in this class, or possibly a class which calls this one. (Think about how difficult it is to unit test this code, for example.)