How to add Order with products attributes from admin panel?

Hey,I have a product with multiple attributes like color, size. when try to add order manullay from admin panel, when search for product and add it, there is no select option to add product attribute. But user want Large size with Black color, so how to select these attributes? Maybe when production type is Variable, if search product, it shows all variables, but when product type is Simple, no attribute select option. Please explain, how to solve this problem.Thanks,Eliyas Hossain