How to use ml.net for recommendation engine?

public void TrainAndWrite()
     {
         var pipeLine = new LearningPipeline();
         pipeLine.Add(new Microsoft.ML.Legacy.Data.TextLoader("path").CreateFrom(useHeader: true, separator: ','));
         pipeLine.Add(new CategoricalHashOneHotVectorizer(("UserId", "UserId")));
         pipeLine.Add(new CategoricalHashOneHotVectorizer(("MovieId", "MovieId")));
         pipeLine.Add(new ColumnConcatenator("Features", "UserId", "MovieId"));
         pipeLine.Add(new FieldAwareFactorizationMachineBinaryClassifier());
         var model = pipeLine.Train();
         model.WriteAsync(@"path../../Model.zip");
         ReadAndEvaluate(model);
     }
     public void ReadAndEvaluate(PredictionModel model)
     {
         var testData = new Microsoft.ML.Legacy.Data.TextLoader("").CreateFrom(useHeader: true, separator: ',');
         model = PredictionModel.ReadAsync(@"path../../Model.zip").Result;
         var alogEvalutate = new BinaryClassifierEvaluator();
         alogEvalutate.Evaluate(model, testData);
         Predict(model);
     }
     public void Predict(PredictionModel model)
     {
         model.Predict(new InputDetails());
     }