As in example it use to save the Customer details based on customer table entity object.
so you need to use your entity name which you are using by table name.
as in example AddToCustomer is used when we click on add button which saves the textboxes values to customersentities object.
so you need to call the save method where you are trying to save the entity details.
Also if have added Entity Data Model with name TestModelNs then only you can imprt the namespace else you need to use same namespace which you assigned when you created Entity Data Model.
also share your code we are not able to access the links.