This is an simple example of how one can use AutoMapper Library

UsingAutomapper.cs

using Models;
using System.Collections.Generic;
using System.Linq;
using AutoMapper;

namespace Data
{
    public class UsersService
    {
        public ICollection<User> Users { get; set; }

        public UsersService()
        {
            this.Users = new List<User>();
            this.Users.Add(new User() { Id = 1, FirstName = "Gosho", LastName = "Ivanov", Age = 11 });
            this.Users.Add(new User() { Id = 2, FirstName = "Atanas", LastName = "Georgiev", Country = "Bulgaria" });
            this.Users.Add(new User() { Id = 3, FirstName = "Spas", LastName = "Trendafilov" });
        }

        public IList<UserViewModel> GetUsers()
        {
            Mapper.CreateMap<User, UserViewModel>()
                .ForMember(u => u.FullName, map => map.MapFrom(p => p.FirstName + " " + p.LastName));

            IList<UserViewModel> userViewModelCollection = new List<UserViewModel>();

            foreach (var currentUser in this.Users)
            {
                UserViewModel userViewModel = Mapper.Map<User, UserViewModel>(currentUser);
                userViewModelCollection.Add(userViewModel);
            }

            return userViewModelCollection;
        }
    }
    
    public class User
    {
        public int Id { get; set; }

        public string FirstName { get; set; }

        public string LastName { get; set; }

        public string Country { get; set; }

        public DateTime DateCreated { get; set; }

        public int Age { get; set; }
    }
    
    public class UserViewModel
    {
        public int Id { get; set; }

        public string FullName { get; set; }

        public int Age { get; set; }
    }
}