Once you have downloaded and unzipped your Action, place your Action in a common folder.
Once you have established that folder, open Photoshop, open the Action palette, click the small triangle in the upper right hand corner to access the fly-out menu, then choose LOAD ACTIONS.
Using the file dialogue, navigate to wherever you have placed your Actions. Click the Load button in the file dialogue, and your Actions will appear at the bottom of the Actions Palette.
You can also drag and drop Actions onto the Actions Palette in Photoshop. For most Actions, it is best to start with a flattened RGB 8-bit image.
Note: Actions have been provided for PS7, CS and CS2/CS3.
Please load the appropriate action for your application.