Today's GOTD can be useful, but not always in the way that some might think. To use them well requires some time, experimentation, and an image editing app that uses layers, e.g. PaintShop Pro, Photoshop etc. Start with your base image, or maybe better, a copy of your base image on one layer, and with one of the images from the bundle on a layer above it. Chances are the 1st thing you'll need to do is size &/or place the bundle's image over your base layer -- temporarily turning the opacity of this layer down so you can see through it can help. With that set, play with the way that layer applies to your base layer, e.g. in P/Shop maybe try Color Dodge. Then if necessary, cut out the parts of the Bundle's image that you don't want, for example selecting all the black in the background, then applying a mask so that that selection's transparent, or maybe adding a gradient mask, so the bundle's image is only applied to a portion of your base image. Then you can go about whatever other tweaking, such as adjusting the opacity of the layer with the bundle's image, adjusting colors for that [or all] layers etc.
The best tip I can offer is not to over categorize... the bundle includes "200 Natural Sun Light Photo Overlays" -- don't feel that you have to use them as the name implies. Yeah, with some like the snowflakes you may have to, but very many, like those Sun Light overlays, can add some really great lighting influences to almost any image. Play around -- sometimes, maybe most times it won't work out, but then you hit on something that's truly amazing. Have Fun! Don't make it into work.