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 have tried several web browsers and tried refreshing the web page multiple times but still, Quest 1 does not allow me to upload a screenshot.