You can find the product in your computer's Desktop folder.
If you’re installing a set of presets from 1 single folder, the automatic method is better.
If you’re installing lots of presets from multiple folders in one, go the manual installation may be quicker.
Automatic installation:
1. Locate the presets from your computer's Downloads folder and unzip the folder.
2. Open Lightroom and go to the Develop module Presets panel and choose 'Import'.
3. Navigate to your Downloads folder of the unzipped presets, select them and press the 'Import' button.
4. Restart Lightroom.
5. Enjoy.
Manual installation:
1. Locate the presets from your computer's Downloads folder and unzip the folder.
2. Find the Develop Presets folder in Explorer (Windows) / Finder (Mac) by going to Preferences > Presets pane and pressing the Show Lightroom Presets Folder button.
3. Copy the presets into that folder, still in their folders if you’d like to keep them organized in the same way.
4. Restart Lightroom.
5. Enjoy.