Once you have installed the programme its icon (IconRestorer) will appear on your Desktop.
Double click on that icon and you will see the opportunity to save your current Desktop icon positions. [In the left hand box.]
Click on that option and a camera will appear to take a photo and you will be told the positions are saved.
Then click on OK and then close the programme.
[Any time you change an icon position and want to save the new layout, just do the same thing again.]
To restore the last previous icon layout, double click on the IconRestorer icon and this time choose to "restore last layout". [The middle box.]
You will be asked to confirm you wish to restore - and that will be it.
Close the programme and the last previous icon layout will have been restored.