If you're referring to Crop Marks, set up your document to 3.5" X 2".
Export your file to PDF and make sure to check Crop Marks in the Marks and Bleeds section of the dialog window. You can also print with Crop Marks directly from InDesign by including Crop Marks in the print dialog.
Assuming you are referring to diecuts, you would need to create a graphic (e.g in Illustrator or whatever) in the shape of the cuts you want (a dieline) and place that in the document where you want the cuts. Use a special spot colour (e.g "dieline", set to overprint) so it can separated by your printer from your underlying artwork. Your printer may have existing standard dies already for this purpose and may be able to supply a graphic of the dieline for you. If this is NOT what you are talking about, please explain further! 🙂