If you know the URL of the server and the name of the feature type that you want to visualize on the map, you can create an ILcdDataSource for it, and pass that to the TLcyDataFormatManager.

static void createWFSModelFromDataSource(ILcyLucyEnv aLucyEnv, ILcyGenericMapComponent<?, ?> aMapComponent) throws IOException {
  //Create a datasource
  String serverName = "https://sampleservices.luciad.com/wfs";
  String featureTypeName = "t_rivers__c__1212";

  TLcdWFSDataSource dataSource = TLcdWFSDataSource.newBuilder()

  //Use the data format manager to load the data on the map
  //This will perform the data loading on the calling thread
  //To avoid blocking the UI, best to execute this method on a background thread and not on the EDT
  TLcyDataFormatManager dataFormatManager = aLucyEnv.getDataFormatManager();
  dataFormatManager.handleDataSources(new ILcdDataSource[]{dataSource},

See Loading data documentation for more details on how to load data on a Lucy map.