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.
Is is possible to cancel an ordered reward? Since I know it probably won't arrive (since most of my experiences with this is just pure disappointment), rather than waiting for it, might as well take back the given SGs and buy something new.
This is for users who actually know something and not for those users who are just desperate to gain experiences (spammers), I won't tolerate spam comments, I will immediately report them.