Play games
Choose the game that interests you and play itfor free.
Complete the tasks
Every game has some tasks 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.
I don't get this, I never played World of Warships before, and I only started making an account for the game just so I can complete the tasks. I reached Level 5 "Free XP", screenshotted it including the timestamp, and then uploaded it here. However, 1 day later, I got a notification saying my task got rejected because it wasn't on a new registered account, which is simply not true.