Mappint 2 or more entities into 1 model (Not AutoMapper)

Question

I have 2 entities which the People and Contact

public class People{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
}
public class Contact{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid Id { get; set; }
public Guid PeopleId { get; set; }
public string Type { get; set; }
public string ContactNumber { get; set; }
}

and I have the model ContactModel to display the entity.

public class ContactModel{
public Guid Id { get; set; }
public Guid PeopleId { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Type { get; set; }
public string ContactNumber { get; set; }
}

my problem is when I'm trying to map the entities to model, I can only map the People entity or one entity and the the two entities.

public static ContactModel ToModel(this People people){
return new ContactModel{
Id = people.Id,
FirstName = people.FirstName,
LastName = people.LastName
};
}