Where do you install brushes in Photoshop? Install the .ABR file you downloaded here:
For a Mac, the path is Go>Library > Application support>Adobe > Adobe Photoshop > Presets > Brushes.
For a PC, the path is Program Files > Adobe > Photoshop > Presets > Brushes.
Once the brush collection is installed then you can open Photoshop. Select the brush tool and then “Load” your brush collection you want to use.