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.
Last night he said "getting ready to use" for the reward. The trade offer was sent from the Steam but it was rejected. How can I get a trade offer again?