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.
Ads play like crazy, and come up every 1-2 levels. I suggest closing the game and reopening it to save time. The game itself is not too difficult, getting past the copious amount of ads was the real challenge