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 mean this is pretty dumb like come on Im not going to make 50 emails because the website doesn't allow the same email like its more spending time on email than the game