How To Use The Photoshop Brushes?
--- First you have to load the ABR file in Photoshop. Go to Edit > Preset Manager and Load the ABR file.
--- Pick the Brush Tool and choose a color for the brush. I use black, blue ink or red for the color of the brush.
--- The size of the stamp brushes is around 1600px. If you use a smaller size, the brush becomes a little blurry. So, after you add the brush in a new layer, I suggest you use the Filter > Sharpen > Smart Sharpen filter to fix this issue.
--- You can combine the stamp Photoshop brushes with a stamp texture to create a more grungy effect.