How to Code a Background Task in .Net Framework 4.7.2 Windows Service

I need a simple example of how to run a background task in my .Net Framework 4.7.2 Console App Windows Service. I know how to do it in .Net Core, but I have an interim application that cannot be upgraded. Thus, I have to find a quick and dirty solution.

The background task I want to run is this (the Update() method):

public class UpdateBackgroundTask
{
    private readonly Settings _settings;

    public UpdateBackgroundTask(Settings settings)
    {
        _settings = settings;
    }
    
    public void Update()
    {
        //first, check the current version and see if it is the same
        //if it is, run away
        var currentVersion = new Version(GetVersion());
        
        //version will be retrieved from the file system somehow...no need to worry about these details
        string version = GetVersionFromFileSystem(); //this method is not in this example           
        
        var newVersion = new Version(version);
        
        if (!currentVersion.Equals(newVersion))
        {
            try
            {
                //fire off a powershell process to update the current running service
            }
            catch (Exception ex)
            {
                //do any error handling
            }
        }
    }
    
    public string GetVersion()
    {
        System.Reflection.Assembly assembly = System.Reflection.Assembly.GetExecutingAssembly();
        FileVersionInfo fileVersion = FileVersionInfo.GetVersionInfo(assembly.Location);
        return fileVersion.FileVersion;
    }
}

How would I wire this up in the Windows service interface start event handler, OnStart?