Need tutorial

Can somebody help me with little problem. I need little tut for "how to change icon on forum" . I wanna put some my own icon for category,forum,topics...etc.
But....
Last time something goes wrong and there is no turning back, i delete last forum
Now i dont wanna mess up again.
I need step by step....

....when i put my icon instead of orginal category icon, my icon doesnt show... orig icon stay there is some radio button hide, bud i dont know what for, if i turn on hide button, i afraid to lose icon forever. Thats why i need step by step tuts...

Please help

tnx
zazz

Admin panel
Styles
List of Pictures

Click on Icons for the Forum

Delete the links to you present images

Click on upload a new picture
Select the image you want

Copy and paste the link of the new picture into the space where you deleted the original picture.

Do that for all the pictures then be sure to click save.

DO NOT CLICK HIDE ON ANY OF THE PICTURES!!