You can check and use the ASTROKINGS coupons when you go to the “Settings” menu and select “Coupon” in the game.
※ Note
In the case of Apple users, the “Coupon” menu may not appear due to the App Store’s policy, so you may need to connect with an Android device or a PC emulator to use the coupon.
▶ How to use the ASTROKINGS Coupon
① Select the “Commander Info” menu at the top left of the planet view
② At the “Commander Info” menu, select “Settings” at the bottom left of the page
③ Select the “Coupon” icon on the “Settings” menu
④ Enter the coupon code at the “Coupon” menu and tap the “Redeem” button
⑤ Check the coupon rewards received through the mailbox