The generic framework can look something like:

using (ClientManager lfclient = new ClientManager())
{
  // Set some print options in preparation for later.
  PrintOptions printoptions = new PrintOptions();
  // Print entire document.
  Laserfiche.ClientAutomation.PageSet pages = new Laserfiche.ClientAutomation.PageSet();
  printoptions.PageNumbers = pages;
  printoptions.DoNotPrompt = false;
  printoptions.DocumentPart = PrintType.Images;

  // Here we're assuming that there's at least 1 instance of the 
  // Client already open.
  IList<ClientInstance> OpenLFClients = lfclient.GetAllClientInstances();
  // Use the first one CAT finds and log in to the desired
  // repository.
  ClientInstance singleLF = OpenLFClients[0];
  LaunchOptions options = new LaunchOptions();
  options.ServerName = "myserver";
  options.RepositoryName = "myrepository";
  MainWindow FolderBrowser;
  singleLF = lfclient.LogIn(options, out FolderBrowser);
                
  // Get a list of entry ids of what's selected in the 
  // folder browser.
  IList<int> selectedDocIds = FolderBrowser.GetSelectedEntries();
  // Print the first selected entry. Hopefully, it's a document.
  FolderBrowser.PrintById(selectedDocIds[0], printoptions);
}