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 think it is pretty fustrating to spend hours playing games, only to find out that you can't submit the task or the reward has been set to normal. This is why i would want a timer to see when the task will expire.