FinalStep is supplied with a series of Code and Control templates that read and write the user variables from and to an .ini file. In this tab, you may specify the name and path of this file.
In addition, inside an .ini file each user in your system may save it own preferences in a different section, thus with the "User Variable" option you specify in which variable you store the user number. This value should be loaded by the security system when you start your program.