Many public scripts are designed to "log" or steal your Roblox cookies , which allows hackers to log into your account without a password.
If you are interested in your own games or legitimate scripts, the Roblox Developer Forum is a great place to start. How to set up a secure account to avoid being hacked? Cheating and Exploiting - Roblox Support
Visit the "More Plots" shop in the game to buy additional space for your mining rig.