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.
So most of the tasks on this website requires you to have a gajin login to play the games, but apparently you can't use the same gajin account if you've already done a different task with it. This is so