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 personally have never bought CS:GO skins, as I'm merely a F2P Player. But I do like some of the CS:GO Skins like AK-47 Bloodspot, M4A4 Howl,... What are your guys' favorite CS Skins?