METHOD 1:
The most convenient way to add a document to a workbook when the document is open in Statistica, is to have the document open and click on "Add to Workbook" from Home tab.

  

METHOD 2:

An alternate way to add a new Statistica document is to determine an appropriate location in the workbook tree and right-click and choose "Insert"

Select the Statistica Document option button in the Item group box and the tree location (either As last child, As first child, As next sibling, or As prior sibling) option button in the Placement group box.The item can always be moved or copied to a new location later using drag-and-drop features, so the exact location is not critical.  Click the OK button to display the Document type dialog.

From the Document type dialog, you may choose to Create new Spreadsheet, Report or Macro or Create from file or Create from Window. For the purpose of this article, create from Window is selected to show how an open window in Statistica can be added to a workbook.

     
 
Result of both Method 1/ Method 2 will be as follows (Document added to workbook) :