public interface IProjectItem 

//create a new FolderConnectionProjectItem
var folderLocationItem = ItemFactory.Instance.Create(@"C:\temp\mydata");
await QueuedTask.Run(() => Project.Current.AddItem(folderLocationItem as IProjectItem);

// Get layout Template Path from the project's home folder and combine it with a file name
var projectPath = CoreModule.CurrentProject.HomeFolderPath;
var layoutTemplateFilePath = System.IO.Path.Combine(projectPath, templateFileName);
// Create a new layout project item with the layout file path
await QueuedTask.Run(() =>
{
  // Create an IProjectItem using a layout template pagx file
  IProjectItem pagx = ItemFactory.Instance.Create(layoutTemplateFilePath) as IProjectItem;
  // Add the IProjectItem to the current project
  Project.Current.AddItem(pagx);
});

//Import a pagx into a project.

//Create a layout project item from importing a pagx file
await QueuedTask.Run(() =>
{
  IProjectItem pagx = ItemFactory.Instance.Create(
                            @"C:\Temp\Layout.pagx") as IProjectItem;
  Project.Current.AddItem(pagx);
});

//Note: Call within QueuedTask.Run()
Item reportToImport = ItemFactory.Instance.Create(reportFile);
Project.Current.AddItem(reportToImport as IProjectItem);