Skapa lista med hjälp av inmatning?

namespace multiListOrArray
{
    class Person
    {
        private string _first_name;
        private string _last_name;
        private int _age;
        private int _ssn;
        private string _city;

        public string first_Name
        {
            get { return _first_name; }
            set { _first_name = value; }
        }
        public string last_Name
        {
            get { return _last_name; }
            set { _last_name = value; }
        }
        public int age
        {
            get { return _age; }
            set { _age = value; }
        }
        public int ssn
        {
            get { return _ssn; }
            set { _ssn = value; }
        }
        public string city
        {
            get { return _city; }
            set { _city = value; }
        }

        public void addInfo(string _fn, string _ln, int __age, int __ssn, string __city)
        {
            _first_name = _fn;
            _last_name = _ln;
            _age = __age;
            _ssn = __ssn;
            _city = __city;
        }
    }
    class Program
    {
        static void personInfo(Person _p)
        {
            Console.WriteLine("First Name: " + _p.first_Name);
            Console.WriteLine("Last Name: " + _p.last_Name);
            Console.WriteLine("Age: " + _p.age);
            Console.WriteLine("SSN: " + _p.ssn);
            Console.WriteLine("City: " + _p.city);
        }

        static void findPerson(List<Person> list, int key)
        {
            foreach (var _p in list)
            {
               if(_p.ssn==key) Console.WriteLine(_p.first_Name + " " + _p.last_Name);
            }
        }

        static void Main(string[] args)
        {
            
            List<Person> manyPPL = new List<Person>();
            Person[] p = new Person[10];

            p[0] = new Person();
            p[1] = new Person();
            p[2] = new Person();

            p[0].addInfo("Kalle", "Svensson", 47, 690202, "Stockholm");
            p[2].addInfo("Glen", "Glensson", 89, 270315, "Göteborg");

            p[1].first_Name = "Sven-Erik";
            p[1].last_Name = "Karlsson";
            p[1].age = 62;
            p[1].ssn = 540122;
            p[1].city = "Umeå";
            
            manyPPL.Add(p[0]);
            manyPPL.Add(p[1]);
            manyPPL.Add(p[2]);

            personInfo(manyPPL[0]);

            Console.WriteLine("\n");

            personInfo(manyPPL[1]);
            
            Console.WriteLine("\n");

            personInfo(manyPPL[2]);

            Console.WriteLine("\n");
            Console.WriteLine("--- --- ---");

            findPerson(manyPPL, 270315);
            
            Console.WriteLine("--- --- ---");
            Console.ReadKey();
        }
    }
}

Output:
First Name: Kalle
Last Name: Svensson
Age: 47
SSN: 690202
City:  Stockholm

First Name: Sven-Erik
Last Name: Karlsson
Age: 62
SSN: 540122
City: Umeå

First Name: Glen
Last Name: Glensson
Age: 82
SSN: 270315
City: Göteborg

--- --- ---
Glen Glensson
--- --- ---

static int personCount = 0;
        static List<Person> manyPPL = new List<Person>();
        static Person[] p = new Person[10];

        static void personInfo(Person _p)
        {
            Console.WriteLine("First Name: " + _p.first_Name);
            Console.WriteLine("Last Name: " + _p.last_Name);
            Console.WriteLine("Age: " + _p.age);
            Console.WriteLine("SSN: " + _p.ssn);
            Console.WriteLine("City: " + _p.city);
        }

        static void addPerson()
        {
            Console.Clear();
            Console.Write("First Name: ");
            p[personCount].first_Name = Console.ReadLine();
            Console.Write("\nLast Name: ");
            p[personCount].last_Name = Console.ReadLine();
            Console.Write("\nAge: ");
            p[personCount].age = Convert.ToInt32(Console.ReadLine());
            Console.Write("\nSSN: ");
            p[personCount].ssn = Convert.ToInt32(Console.ReadLine());
            Console.Write("\nCity: ");
            p[personCount].city = Console.ReadLine();
            manyPPL.Add(p[personCount]);
            personCount+=1; 
        }

        static void Main(string[] args)
        {
            for (int i = 0; i < 9; i++)
            {
                p[i] = new Person();
            }

            addPerson();

            Console.Clear();

            personInfo(manyPPL[0]);

            Console.ReadKey();
        }