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.
As I bounce around with my tanks more often than not, the possibility of gaining an MOE is questionable because if I play with one tank straight thru I suffer more losses than anything ... and manage to do less work. How long did you have grind in any one tank to get your first MOE? And which tank was it? Ironically I finally got my WN8 up to 999 yesterday, but it dropped ... I've had some recent high damage battles including my first over 4K match ...