How to open an Excel Sheet and Use conditional formatting to change cell colors depending on existing results in C#

Question

In the most simplest,shortest,easiest understandable words:

I have a program that automatically creates and output results of a tests into an excel file. Wherever it says PASS in the results column I want the cell color to change to green or else if its FALSE I want to change it to Red.

How would I do this?

Current Code for Exporting Results: (Comments Asked for it)

    using System;
    using System.Collections.Generic;
    using System.IO;
    using System.Linq;
    using System.Text;

    namespace PortfolioVariations
  {
public class FileOutputter
{
    private const char DELIM = '\t';
    private VariationRunConfig Config { get; set; }

    public FileOutputter(VariationRunConfig p_Config)
    {
        Config = p_Config;
    }

    private string CreateOutputRow(RunResult p_From)
    {
        const string passed = "PASS",
            failed = "FAIL",
            error = "ERROR";

        if (p_From.HasWebsiteResult)
        {
            string passedStatus = p_From.GetHasPassed() ? passed : failed;
            return $"{p_From.TestCaseNumber}{DELIM}{passedStatus}{DELIM}{p_From.TestCaseExpectedAmount:C}{DELIM}{p_From.GetPriceText()}{DELIM}{p_From.TestCaseStatus}{DELIM}{p_From.Result}{DELIM}{p_From.QuoteRef}{DELIM}{p_From.ExpectedEndorsements}{DELIM}{p_From.ActualEndorsements}";
        }
        else
        {
            return $"{p_From.TestCaseNumber}{DELIM}{failed}{DELIM}{p_From.TestCaseExpectedAmount:C}{DELIM}{error}{DELIM}{p_From.TestCaseStatus}{DELIM}{error}{DELIM}{error}";
        }
    }

    public string DoFileOutput(IEnumerable<RunResult> p_Results, TimeSpan p_TimeTaken)
    {
        if (!Config.EnableOutput)
        {
            return string.Empty;
        }

        string outputFileName = Path.Combine(Config.OutputFolder, string.Format(Config.OutputFileNameFormat, DateTime.Now)),
            outputResult = new[] { $"{p_TimeTaken.Hours}:{p_TimeTaken.Minutes}:{p_TimeTaken.Seconds}",

                $"Case{DELIM}Result{DELIM}Expected Premium{DELIM}Actual Premium{DELIM}Expected status{DELIM}Actual Status{DELIM}Quote Reference{DELIM}Expected Endorsements{DELIM}Actual Endorsements"}
        .Concat(p_Results.Select(CreateOutputRow))
        .Aggregate(new StringBuilder(), (sb, s) => sb.AppendLine(s)).ToString();

        using (StreamWriter of = new StreamWriter(outputFileName, false, Encoding.Unicode))
        {
            of.Write(outputResult);
            of.Flush();
        }

        return outputFileName;
    }
}
}