There's a full tutorial for a same thing but for insanejournal here.
Basically though:
1) Unzip the folder somewhere. 2) Place icons in the 'THE ICONS' folder which I'm pretty sure I left in. 3) Open up the 'Upl' file which will bring up a DOS window. 4) Type in your username, hit enter, type in your password and then hit enter again and it will upload all the icons in the 'THE ICONS' folder!