elastic search field update from csv file in c#

I am new to programming in C# I want to read the csv file and update the fields in elastic search. I already have this function made by someone else and I want to call this function and update fields.

 public static bool UpdateDocumentFields(dynamic updatedFields, IHit<ClientDocuments> metaData)
        {
            var settings = (SystemWideSettings)SystemSettings.Instance;
            if (settings == null)
                throw new SettingsNotFoundException("System settings have not been initialized.");

            if (ElasticSearch.Connect(settings.ElasticAddressString(), null, out ElasticClient elasticClient, out string status))
            {
                return ElasticSearch.UpdateDocumentFields(updatedFields, metaData, elasticClient);
            }
            
return false;
        }

what I have done myself so far is :

  private void btnToEs_Click(object sender, EventArgs e)
            {
                var manager = new StateOne.FileProcessing.DocumentManager.DocumentManager();
                
                var path = "C:/Temp/MissingElasticSearchRecords.csv";
                var lines = File.ReadLines(path);
                foreach (string line in lines)
                {
                    var item = ClientDocuments.GetClientDocumentFromFilename(line);
                    if (item != null)
                    {
                        var output = new List<ClientDocuments>();
                        manager.TryGetClientDocuments(item.AccountNumber.ToString(), 100, out output);
                        if (output!= null && output.Count <= 0)
                        {
                            var docs = new List<ClientDocuments>();
                            //var doc = docs.Add();
    
                            // var doc = docs.Add();
                            //docs.Add(doc);
    
                            foreach (var doc in output)
                            {
    
                                if (!item.FileExists)
                                {
                                    //insert in elastic search 
                                    manager.UpdateDocumentFields(output, );
                                }
                                else
                                {
                                    //ignore
                                }
                                
                            }

My problem here is manager.updateDocumentFields() is a function. I am calling it but what I need to pass as a parameter? Thanks in advance.