Here's a quick idea as to which photos you can use the 4 effects:
--- Light Rays Effect can be used for indoor photos
--- Sneak Peak Effect can be used to focus mainly on the important aspect / part of the subject
--- Outdoor Botanical Effect can be used for scenery, beaches, and where there's greenery
--- Psychedelic Effect can be used to set the mood of the environment or subject

To add your photo:
just double-click the smart-object layer at the bottom with the name "Add Your Photo" and add your photo and save. Once you add your photo, trying hiding and unhiding the relevant effect folder to see your result. You can easily adjust the contents within the folders as well. You can also move around your photo layer to adjust your desired view, if necessary.