Complete Event Objectives to earn Hero Coins, then use them to unlock rewards along the Reward Paths. Each Path contains different rewards, but you can choose which Reward Path you want to explore. You can also jump between Reward Paths freely when they merge or cross over - as long as you have enough Event Keys and Hero Coins.
Note: you can only move down or sideways along a Path, you cannot move upwards.
Hero's Path
You'll need Event Keys to head down certain Paths or to cross over to another. You may be given one Event Key for free when the Event starts, but most of the time, you'll need to use the Hero Coins you earn during the Event to get some.
When the Event ends, any unused Event Keys will be lost and any unused Hero Coins will be lost and automatically converted to Silver. Throughout the course of the Event, it is not possible to earn more Hero Coins than is required to unlock all of the Rewards.