Step 2: There will be a new screen that pulls up with several tabs at the top. Click on Presets (the second tab).
Step 3: Click on the box titled, Show Lightroom Presets Folder if you are on an older version of Lightroom. If you are on a newer version of Lightroom Classic, click on the Show All Other Lightroom Presets box.
Step 4: Double click on Lightroom.
Step 5: Next double click on Develop Presets Folder.
Step 6: Copy the contents of the Presets Folder, found in your download, into the “Develop Presets” folder.
Step 7: Finally, restart Lightroom and you’re finished! Your presets are now installed. To apply them, open the Presets panel on the left side of your screen and use the small triangle to open the folder. Click a preset in the folder to apply it.
(Source: https://www.lightroompresets.com/pages/how-to-install-lightroom-presets)