I’m little confused with how a ViewModel should be structured.

A generic example would be Customer with a list of Orders.

Should there be 3 viewmodels?

CustomerViewModel – list of fields that applies to this …

OrdersViewModel – list of field that applies to this… 

public class CustomerOrdersViewModel
{
public CustomerViewModel Customer{ get; set; }
public OrdersViewModel Orders { get; set; }

}

To display a view with Customer details at the top as Master Details then show a grid of Orders that relates to the Customer.

I am using CustomerOrdersViewModel.

Is this the correct approach?

alphabeatsco

A generic example would be Customer with a list of Orders.

Should there be 3 viewmodels?

f you have one View, then it will be one ViewModel.  

My objective is to create a page which has the Customer Details at the top.

Below is a list in a Kendo Grid with all its Orders.

How should my viewmodel structure look like?

Your plan looks good? no issue.

in other way, You can have a property Orders of type
OrdersViewModel directly to the CustomerViewModel.  Setting the value to this
Order property is depending on what you want to display on view ( Only customer detail or customer with orders)

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