Before you start building any app, the following you need to typically have.
Computer and Operating System
- Macintosh (with Intel processor): Mac OS X 10.5, 10.6
- Windows: Windows XP, Windows Vista, Windows 7
- GNU/Linux: Ubuntu 8+, Debian 5+
- Mozilla Firefox 3.6 or higher
- Apple Safari 5.0 or higher
- Google Chrome 4.0 or higher
- Microsoft Internet Explorer 7 or higher
Google has a very easy guide on how to setup and get started. After you setup make sure to go through the contents on learn section. There you will find the Reference Documentation, the basic Tutorials, and everything else that you need to get started. If you need to ask questions, you can do so in the Forum. Visit the Blocks & Tutorials section where you can find tutorials on using different app inventor blocks. It’s always better to try some Sample Apps first to see the bigger picture.