You can participate in Airship Trial to earn materials and gold.

1. Participate in the Airship Trial to earn materials to upgrade your heroes and equipment when reach commander's level 25.  

2. Every day, players have two chances to each type of trial. Number of chances will be decreased after victory. 

3. Upgrading your Commander level unlocks tougher challenges and therefore, larger rewards. 

4. Higher VIP level can acquire more challenge attempts