If you add it in ux folder you will have skin auto enabled when you turn on igo and you can't change it in settings display
If you like to use skin from igo/content/skin/ folder, then you must also write your resolution in sys.txt

So if you don't have ux folder in iGO folder then create it and do like this:

- open folder iGO/ux/ and add inside skin .zip
- now run iGO and you will see that Dimka skin is already enabled