Maybe for someone like you, it might not need any knowledge, but imagine a guy who just got the program and have no idea what a layer box is? And fine I used the 'term' render wrong, what I meant was to put a texture on a picture.
And I think it is worth a guide, because many people ask how to make icons and I thought it would be nice of me to make a guide for people who wanted it.
Sure this isn't amazing or unique, but it's a start. A designer can simply after a few tries try some new techniques. This is only made for you to get started. If you don't believe me visit his
thread, and look at his amazing icons.