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 don't really get this game, given the fact there is not a lot of detail to it.
Please if somebody could explain how to play this game it would be very helpful.