How to use alpha brush pack:

After downloading unzip file and add to your favorite 2D/3D paint program to use for sculpting and/or painting details on your models.

In Blender 2.8+ you can add these alpha brushes as sculpt brushes easily as well by going to the sculpt tab, choosing create new brush option, add new texture, then adding one of the alpha brush images to your new texture to then paint with.

Tip: Using different levels of pressure, flow, rotation, size, and depth intensity you can create very different effects with a single brush.