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 think those new avatars are pretty weird, i think they might be planning to remove the old ones we use this days, if they do that i'll 100% quit roblox and a lot of people will do aswell