Like my sweet snow globe overlays and templates, these work in a similar way.
This video will walk you through using the template, included in your set. You will also find PNG overlays included in the set, so if you don't want to use the template, you can use those instead!
Don't be scared of using the template, though! Once you have walked through the steps you will find it much quicker to add your images there, rather than having to use layer masks to remove snow or glows from your edit.