You can only get Soulstones from events at the moment, such as "Sign-in and Win Prizes!", forum events, and other events. Soulstones won from events are sent to your in-game mailbox.
After collecting the Soulstones, you can see them in the Hero Compendium. For example, if you have 20 Pumpkin Duke Soulstones, you'll see 20/200 on the Pumpkin Duke in the Hero Compendium. You can redeem a Hero card with 200 of the corresponding Soulstones, which will be placed in your Warehouse.
To access Hero Compendium, please tap the button at the bottom of the screen, then tap the second icon marked with red arrow.
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