looking for a tutorial

I'm looking for the icon tutorial for such icon.
It is my own, but I know for a fact that I used a tutorial.
I had it bookmarked on my old computer, but I never added it to memories.
If anyone could give me a link that'd be great!
I've checked the archives, and couldn't find it so I'm not sure if they deleted it or not.

EDIT: This has been solved thanks :)