IMO you must have a look at http://community.qlik.com/docs/DOC-2026 (Video)
It is NT Name security. I have even attached you a file in the morning on your earlier thread.
Use the same file or excel sheet to create Joins, Section Access and Section Application as a sample.
Besides that your NT name will be the user ID of your computer. You can check that =OSUser() using a text box.
Hope this helps.