One to Many Relationship

Question

Good afternoon, I am new in asp net. I am building some System EPI Management . I dont know how i could do what i want, I have a Product class with those atributes

public class Produto
{
[Key]
public int ProdutoID { get; set; }
public string Nome { get; set; }
[Display(Name ="Descricao")]
public string Desc { get; set; }
public int FornecedorID { get; set; }
public virtual Fornecedor Fornecedor { get; set; }
public int CategoriaID { get; set; }
public virtual Categoria Categoria { get; set; }
public string Armazem { get; set; }
[Display(Name ="Unidades Metricas")]
public int UnitMID { get; set; }
public virtual UnitM UnitM { get; set; }
}

and I have a Employee Class too, Iam using Code First. And i do have a Entrada Class is a ReceiveGoods class

public class Entrada
{
[Key]
public int EntradaID { get; set; }
public string MotivoEntrada { get; set; }
public string Nota { get; set; }
public int GetIDFuncionario { get; }
public IEnumerable<Produto> Produto { get; set; }
}

In the class Entrada i want to select more than one pruduct. i dont know how to to. I tried Dropdownlist is keep showing me error. help me, the need is to add many products as possible.