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.
So I've just started playing this game, to be honest it's better than I thought it would be, not sure why I haven't downloaded it before! Any tips or advice about anything I should know? :)