Representing JSON Groups in an C# Object

I'm playing around with MongoDB and trying to write some JSON documents to MongoDB.  Currently, I am hard coding the values and outputting to the screen.  The end goal is to migrate data from SQL Server to MongoDB, but until I can get the initial Class working correctly (hard coded method), I can't really proceed.

Let's say I have some financial securities and tickers.  Currently, in SQL Server, these are in seperate tables (dbo.Security and dbo.Ticker) with SecurityId being the PK/FK.

I have added a few documents manually, using this JSON document:

{"SecurityId": 1234,"CompanyId": 1,"SenderId": 2,"TradingAccountId": 1,"InstrumentDescription": "VODAFONE","InstrumentTypeId": 5,"ImportId": 1,"Ticker" : [ { "TickerType" : "CUSTOM", "TickerValue" : "VODA1" }, { "TickerType" : "ISIN", "TickerValue" : "XS123456789" } ]
}

This works fine.  I can run this in the MongoDB shell and add a document.  Initially, I created a single class that did not represent any Ticker data and that worked great.  Now I wanted to save the tickers with the security, so I googled around and stumbled across a List which seemed to fit the bill, but I can't figure this part of the class out.

Here is what I came up with (mostly via Google searches).  I've excluded the include, namespace parts of the .cs files.

Ticker Class (Ticker.cs file):

    class Ticker
    {
        public string TickerType { get; set; }
        public string TickerValue { get; set; }
        public bool Default { get; set; }
    }

Security Class (Security.cs file):

    class Security
    {
        public int InstrumentId { get; set; }
        public int CompanyId { get; set; }
        public int SenderId { get; set; }
        public int TradingAccountId { get; set; }
        public string InstrumentDescription { get; set; }
        public int InstrumentTypeId { get; set; }
        public int ImportId { get; set; }
        public List<Ticker> SecurityTicker { get; set; }
    }

Form1.cs:

            Security sec = new Security
            {
                InstrumentId = 1,
                CompanyId = 1,
                SenderId = 1,
                TradingAccountId = 1,
                InstrumentDescription = "ABCD",
                InstrumentTypeId = 1,
                ImportId = 1
            };
            string json = JsonConvert.SerializeObject(sec, Formatting.Indented);

What I can't figure out is what code is needed to write data into the SecurityTicker List.  This could be no tickers or multiple tickers.

Initially, I figured something like:

SecurityTicker.Add........

But all I get is a tool tip with "Invalid initializer member declarator".

Now, I am stuck.  To be honest, I don't even know if this is the correct approach to load data into a class and then serialize it into a JSON document.

Any advice is welcome!  If you need more information, please let me know.

Thanks!