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.
Perhaps I am over thinking things... but what makes people wanna suicide scout? I've had a few tonight rush straight to the enemy capital as fast as they can and try to kill the enemy arty at game start. It rarely, if ever works, they get mowed down by several tanks at once. What is the point? What is the logic in trying such a feat? I can't think of a rational reason to just see how fast you can go back to the garage.