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.
I believe you should put an additional rule to the proposed games that tasks will be generated. The game should be free, so everybody can have access to that game. I have seen many say For Honor (which is a great game but it's paid) and Minecraft and Rocket League and GTAV. They also suggested Valorant which is not released tin all regions yet. I believe some extra rules would be great for this. Thanks.