Double-click on the ATN file. Choose the ATN file that corresponds with your version of Photoshop.
Go to your Actions panel (Window > Actions) to find the actions.
Note: If you do not see the actions, click on the panel menu (top-right corner of the Actions panel) then click Load Actions. Browse for the ATN file then click Load.
Using the Photoshop Actions:
In the Actions panel (Window > Actions), click on the "Play All Effects" action.
Go into your History panel (Window > History) and select an effect.
Adjust the layer opacity to change the strength of the effects.
For extra contrast, make the "Extra Contrast" layer visible.