1. Where should we save our app data to on the Playbook?

Files for unrestricted use by the user, and certainly if to be used with other apps, go in documentsDirectory or userDirectory, but there's currently no distinction between them so pick whichever feels best to you.
If you don't mind some PB-specific support, consider adding one of the listed subfolders below the userDirectory, with things like File.userDirectory.resolvePath('photos/myimage.jpg').
App data that is to only be used with your app should be saved in the applicationStorageDirectory

2. How to navigate between screens in an app?

Navigating through pages/screens is simply a matter of adding and removing the relevant pages (children) as necessarry.

3. How to test an orientation change on the simulator?

Swipe up from the bottom right corner of the device.

4. What size should an apps icon be?

86x86. Icons larger than this will not display. For more info read the docs.

You will also need 480x480 icon for display in Blackberry App world.

5. How to access the GPS/Camera/Accelerometor on the simulator?

There is no way to access these with the current simulators.

6. Will MouseEvents trigger from a touch?

Every TouchEvent will also fire off a MouseEvent, so you should be fine. However, MouseEvents will not be abel to handle Multi-Touch input.

7. How to lock screen orientation to landscape mode?

In your *-app.xml file under <initial window> make sure these values are present:



8. How to code sign a app?

This thread provides a walkthrough for signing your app. If you have any issues, please read through the whole thread. Chances are your issue is discussed there.

9. Tell us what you know about BlackBerry Tablet OS?

BlackBerry Tablet OS is an operating system from BlackBerry Ltd based on the QNX Neutrino real-time operating system designed to run Adobe AIR and BlackBerry WebWorks applications, currently available for the BlackBerry PlayBook tablet computer. The BlackBerry Tablet OS is the first tablet running an operating system from QNX, the company responsible for real-time operating systems used in products from cars to nuclear reactors. QNX is now a subsidiary of RIM.