Linking Through the Ages (LTTA) is a guidebook for Mystcraft, a mod that adds elements from the Myst series of video games by Cyan, Inc. Mystcraft does not come with any in-game instructions, so Linking Through the Ages is made to fill that void. Ready-to-play jar files are hosted on CurseForge.
Linking Through the Ages is not made to be used alone. It requires both Mystcraft and Guidebook to add the guidebook and display its contents properly. By default, a book is given to every player on first spawn. You can disable this feature in the config file.
Please feel free to use the "Issues" link above to report any problems you encounter while using this mod, but I will refer you to the Mystcraft and/or Guidebook authors if the issue is with their mods.