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.
Does the reward really usually take around 72 hours or at least 5+ days to dispatch? Not saying this site is a bit sketchy or anything, just curious about how many days yours have actually arrived cuz y'know.
I wasn't entirely sure about that ¯\_(ツ)_/¯