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.
For a free to play game, World of Tanks is exceptional good value and fun. I'll be sticking to this game for quite a while, since they project it to run for at least 5 years, with content and new features added during the lifespan of the game. The next addition to the game, a global Clan Wars persistent world fighting for territories is going to be introduced this summer and sounds very interesting. Untill then I am playing with my clan mates in platoons and tank company battles, and thouroghly enjoying it.