Placeing Markers

Hello , I'm stuck on something and i would like to ask for  some help , maybe someone can guide me here.What i want to achieve is to place a marker on each of the periods/slices//instances (have no idea how they are called) if the Opening Price and Closing Price is more then X% of the total bars height (High , Low).

I'm a hobbyist  programmer so  probably im asking some basic stuff here.  So Far I managed to make a line that almost shows the thing i want but i want characters to show the places not a line going there from the previous

namespace cAlgo.Indicators
{
    [Indicator(IsOverlay = true, AccessRights = AccessRights.None)]
    class MuIndicator : Indicator
    {
        [Output("Main")]
        public IndicatorDataSeries Result { get; set; }

        [Parameter(DefaultValue = 40)]
        public int BodySizeLimit { get; set; }

        public override void Calculate(int index)
        {
            var itsBull = true;
            var LineLength = MarketSeries.High[index] - MarketSeries.Low[index];
            var BodyLength = MarketSeries.Open[index] - MarketSeries.Close[index];
            if (BodyLength < 0)
            {
                itsBull = false;
                BodyLength = BodyLength * (-1);
            }

            var BodyProcentage = BodyLength / LineLength * 100;

            if (BodyProcentage < BodySizeLimit)
            {
                if (itsBull)
                {
                    // put a smily face above with green color
                }
                else
                {
                   // put a sad face beloved with red color
                }
            }
        }
    }
}

I would  like to achieve something like this: