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.
You can exchange your Soul Gems for Steam Wallet top-ups, game keys, CS:GO Skins and other rewards.
I never had problem till yesterday when I didn't recive reward for my task it was 400+SG https://imgur.com/a/LGwrSt7 will they accept my quest or nah? been 24+h