Starting next Tuesday, each time you kill a champion enemy in Central Tyria maps, you’ll receive a Champion Mark in addition to normal loot drops. Trade Champion Marks to Consortium officers in capital cities in exchange for Bonus Boxes of Goods. You can find them by clicking on the Special Event notice in the UI. Trading Champion Marks to vendors in capital cities will progress the overall community goal. You’ll receive rewards for each tier you participate in.
https://www.guildwars2.com/en/news/champion-rush-begins-next-week/