Go to Window > Actions. Click on the panel menu (top-right corner of the panel) then click Load Actions. Browse for the "Premium Looks by SparkleStock.atn" file then click Load.
Using the Photoshop Actions:
In your Actions panel (Window > Actions), click on the "Play All Effects" action.
Go into your History panel (Window > History) and select an effect.
Click on the "Play all Light Leaks" action in your Actions panel.
Select a light leak effect from your History panel.
Tips
Easily adjust the strength of the effect by changing the layer opacity.
Duplicate the layer to increase the strength even more.
You can transform the light leaks by converting them to a Smart Object. Select the layer group containing the light leaks then go to Layer > Smart Object > Convert to Smart Object. Change the blending mode back to Linear Dodge. Now you can resize and move the light leak.