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.
Gamehag is a legit website that pays out its users. Additionally, it's also a pretty strong to other companies in the space like Gamekit, which also pays you for playing PC games. Most websites that pay you for playing games are fairly similar to one another and don't have the greatest game selection.