After the Paypal payment process you will automatically receive an e-mail with the download link to your preset or your presets.
The presets can be conveniently used for Lightroom Mobile in combination with the desktop application. The presets are saved in .xmp file format and automatically sync from desktop to mobile. JPEGs can also be edited with the presets, as they only contain a color look in them, they are primarily intended for use with raw files. Here is a guide to editing with my presets.