THIS IS A DATAPACK! You need to either add it to your world's datapack folder or use an automatic loader such as OpenLoader or Paxi.
This datapack makes certain spellbooks from the RPG Series and unofficial addons become tiered, requiring to craft them.
How to install?
Download the zip and put it in your world's datapacks folder.
Alternatively, install openloader or paxi, and put the datapack inside their data folder.