Play games
Choose the game that interests you and play itfor free.
Complete the quests
Every game has some quests for which you will receive Soul Gems.
Receive rewards
You can exchange your Soul Gems for Steam Wallet top-ups, game keys, CS:GO Skins and other rewards.
I've got the message "A task for War Thunder has been rejected.. Make sure you did everything right, and upload a new screenshot". My Name & the Task (number of won battles) are clearly visible. Anything I'm missing? How do you do it?