Guidebooks are the best way to look in-game for details about the Add-On. If you've lost or accidentally deleted your Guide Book then you can re-craft them:

FARMING

Use a Minecraft book and one Wheat in a crafting table.

RPG SKILLS

Use a Minecraft book with one Minecraft pickaxe in a crafting table.

TRAINS

Use a Minecraft book with one Gold Nugget.

MACHINES

Use a Minecraft book and one Redstone.