How to use it.

First pick your icon, then name it & tap copy.
Go to the Folder, the icon is for & hold it till it wiggles.
Tap the folder & delete name of the folder.
Hold your finger over the folder name bar till "Select / Select All / Plate" pop up.
Tap plate, your icon & name should fill the name bar.
push your home button & your done.

For SpringBoard it just means Home Screen.

mpb25metal about FolderIcons, v1.0