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 the title says, there should be an option for a group chat. If the website wants to make it easier to socialize and hence stick here longer and more often, I believe group chats are essential.