!!! UPDATE to VERSION 1.1 !!!
If you want to develop in your own structure like:

and you will deploy it for device you must copy the lua files in the main folder.
Ansca wrote for required : These Lua files MUST be in the same directory as your main.lua file in order to be packaged for you during device builds, otherwise require() will fail at runtime. Please also see the note below about file name case sensitivity.
With the Air Corona Project Builder you can develop by your own structure and if you want to build it for device you just choose your Project folder and all files are managed in one folder also require(“path”) in the LUA files will be updated !
Note that you can use only Project folder and in there sub folder not in sub folder –> sub folder!!!
NOW YOU CAN USE SUBFOLDERS !!!
And don´t name your folder like the class –> folder name= assets –> assets.lua !!!

But just try it out and give me a feedback if you like it
Download Air File : CoronaProjectBuilder
Here is a little how to for Windows works also with Mac !!!
You can use FDT or just Eclipse.
Basic:
- Create a Account and download Corona for windows or mac.
- Install Corona and run Simulator for register.
- close Corona Simulator
FDT:
- in FDT or Eclipse select Help ->Install New Software

- Add new lua Site Type Name and copy this Location: http://luaeclipse.luaforge.net/update-site/site.xml

- now you will see this. check out the LuaEclipse 1.1 and click next for install.
- if the install progress is done FDT or Eclipse will restart.

- Now open a new Lua Project : select File -> New -> New Lua Project

- Enter a Name for your Project and click Finish

- Now select Window -> Preferences

- and open Lua -> click Add
- Enter the name of Interpreters as Example : “Corona Simulator” and browse to the path of your Corona Simulator.exe File

- Now you check your New Interpreter
- click OK

- now copy a sample code in your new project like this one and open the main.lua file

- ok now we will run the file
select Run -> Run As -> (or click the green arrow button)

- you will see your App on the Simulator… Thats all !!

Hope you enjoy this little how to