Roblox Studio is the place where any Roblox Experience is made.
With thousands of tools and objects that can help you, it makes it easier than building a game on other platforms such as Unity.
Roblox Studio has millions of community-made plugins that can speed up your developing process, giving you more time to work on other things.
They also have millions of models, sounds and images for you to choose from that help you develop!
It can be downloaded for free here.