How to make DTOs for complex models - .net-core

Question

My target with the below mentioned classes is to make one DTOs class out of these classes and register AppUser in sqlite database. I use Identity core. I thank you for every body who has given me help on solving this problem.
By the way: is that possible to have virutal properties inside DTO classes? Other thing which i am struggling with is on how to handle the incoming user input (in this case DTO). I get the following error time and again Cannot implicitly convert type int to Backend.Data.Gender. I Cannot implicitly convert type Backend.Data.Work_Experience to System.Collections.Generic.List<Backend.Data.Work_Experience>
public class AppUser : IdentityUser<int>
{
public string FirstName { get; set; }
public string LastName { get; set; }
public string Description { get; set; }
virtual public Gender Gender { get; set; }
virtual public ICollection<Interest> Interests {get; set;}
virtual public List<Education> Education { get; set; }
virtual public List<Work_Experience> Work_Experiences { get; set; }
virtual public List<Answer> Answers { get; set; }
}
public class Interest
{
[Key]
public int Id { get; set; }
public string InterestName{ get; set; }
public virtual ICollection<AppUser> Users { get; set; }
}
public class Education
{
[Key]
public int EducationsId { get; set; }
public string SchoolName { get; set; }
public string Field_Of_Study { get; set; }
public string StudyPath { get; set; }
public DateTime StartDate { get; set; }
public DateTime EndDate { get; set; }
public int DegreeId { get; set; }
public virtual Degree Degree { get; set; }
public int UserId { get; set; }
public virtual AppUser User { get; set; }
}
public class Degree
{
[Key]
public int DegreesId { get; set; }
public string DegreeName { get; set; }
}
public class Gender
{
[Key]
public int GenderId { get; set; }
public string GenderName { get; set; }
}
public class Work_Experience
{
[Key]
public int WorkExperiencesId { get; set; }
public string JobTitle { get; set; }
public string CompanyName { get; set; }
public string Industry { get; set; }
public string Field_Of_Work { get; set; }
public int UserId { get; set; }
public virtual AppUser User { get; set; }
}
public class Question
{
[Key]
public int QuestionsId { get; set; }
public string Question_text { get; set; }
}
public class Answer
{
[Key]
public int AnswersId { get; set; }
public string Answer_text { get; set; }
public int QuestionId { get; set; }
public virtual Question Question { get; set; }
public int UserId { get; set; }
public virtual AppUser User { get; set; }
}