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 heard about "the golden bat of gamehag" which gives you 5 sg if you click on it, but i don't know where to look for it. Does anyone know where to find it?