This is how to load brush files with .abr file extension to your photoshop.
This file is a Photoshop brush preset.
At first I happened to download the .abr (Adobe Brush) and didn’t know how to use it with photoshop.
What I did was I copied the file and place it in Program Files\Adobe\Adobe Photoshop \Presets\Brushes.
It didn’t work, because it was not only placing the file in a right place, but we have to do other things to.
Once you got it loaded in PS and you still can not find it, you may want to close the application and re-open it again.
I found it very easy once you know how to do it.