How to create index of ElasticSearch NEST v.5 client by using custom analyzer?

What is the right way to create index by using NEST v.5? I saw the similar post here: Specifying and using a NGramTokenizer with the C# NEST client for Elastic Search. But it seems that API was changed. I can do it the following way:

ConnectionSettings settings = new ConnectionSettings(new Uri("http://localhost:9200"));

IndexSettings indexSettings = new IndexSettings();
            CustomAnalyzer customAnalyzer = new CustomAnalyzer();

customAnalyzer.Tokenizer = "mynGram";
            customAnalyzer.Filter = new List<string> { "lowercase" };

            indexSettings.Analysis.Analyzers.Add("mynGram", customAnalyzer);
            indexSettings.Analysis.Tokenizers.Add("mynGram", 
                                                  new NGramTokenizer
                                                  {
                                                      MaxGram = 10,
                                                      MinGram = 2
                                                  });

elasticClient = new ElasticClient(settings);

            elasticClient.CreateIndex("taskmanager", s => s
                .Settings(sett => sett
                    .Analysis(a => a
                        .Analyzers(anl => anl
                            .Custom("customAnalyzer", c => c
                                // how to set my custom analyzer?
                                .Tokenizer("mynGram")

                            )
                        )
                    )
                )
            );

The problem is that I don't know how to set my settings by using fluent API.