A .ini file is a file that contains all the scripts and codes that the program will follow to perform certain tasks, but I dont know where are you getting this file since all theme suites are zipped into a .suite format.
After you download a suite, it will be place automatically in the ThemeManager Theme folder. All you have to do then is:
-Open the ThemeManager/WinStyle program.
-Scroll down the list for the theme you want to apply.
-Click on it once to highlight it.
-Click the Apply button, and the program will do the rest.
BTW. Keep in mind that you need the nescesary program to apply all the skins in the theme. Per example, if the theme suite has a WB, Cursor, IconPack, Logon, BootSkin, etc. You need to have each of those programs installed.