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 noticed that even the large open world maps like jailbreak are kinda small. (for open world maps) Is this because there is a size limit or they're just being lazy?