How to properly group data in LINQ? (Group by in C#)

Hello everyone! I just started learning LINQ in C# and encountered a problem when using GroupBy. I have a list of orders, and I want to group them by customer name to see how much each customer spent. Here is my code: ```csharp public class Order { public int OrderId { get; set; } public string CustomerName { get; set; } public decimal Amount { get; set; } public DateTime OrderDate { get; set; } } List orders = new List { new Order { OrderId = 1, CustomerName = "Ivan", Amount = 250, OrderDate = DateTime.Now.AddDays(-1) }, new Order { OrderId = 2, CustomerName = "Maria", Amount = 400, OrderDate = DateTime.Now }, new Order { OrderId = 3, CustomerName = "Ivan", Amount = 150, OrderDate = DateTime.Now.AddDays(-2) }, new