Drop into your Skyrim Special Edition Data folder.

Example: D:\SteamLibrary\SteamApps\common\Skyrim Special Edition\Data

Load Order:
<esms>
Weightless Books - Base.esp
Weightless Books - Update.esp
Weightless Books - Dawnguard.esp
Weightless Books - Hearthfires.esp
Weightless Books - Dragonborn.esp