Creating a game can be very difficulty, even for Roblox Studio. You will have to first understand how the software works and what it provides, then you have to establish what game you want to developed and what you need it to do.
Luckily, the developers have a Wiki page filled with information on how to work with Roblox and basically create games. There are tutorials you can follow to learn how to create games.
Access the following page to go to the Wiki section.