How to use Landmarks

About Root: Landmarks Pack, from BoardGameGeek:

Bring the Root Woodland to life with landmarks! Landmarks add unique powers to their clearings and can be added to games with any player count. The Landmark Pack includes four screen-printed wood landmarks: Barter for anything you need at the Black Market. Find new friends and followers in the Lost City. Craft a masterwork at the Legendary Forge. Sit proud upon the grand throne in the Elder Treetop.