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.
Im playing Roblox for many years, It is a really fun platform. I also tried to create my own games but its hard especially if you are new to scripting and modelling. Roblox has ups and downs but I still enjoy it so yeah. I only play few specific games on Roblox because whether you like it or not some games are just not for your taste.