You can find out everything requested on the application by running existing tools on your Windows system. The easiest way to find that information is to use the DirectX Diagnostic Tool. Click Start, then Run, then type dxdiag in the window and press OK. The DirectX Diagnostic tool will open. You may be asked if you want to allow checking for digital signatures (I usually allow that - it's harmless). On the first page of the the tool (the System tab), you can find information about your computer and DirectX version. To find your VRAM, click on the Display tab, and you should see your display adapter's specifications in the upper left corner, including your VRAM (right above display mode).
It's best to supply all of the requested information, since I will be selecting beta testers based on the information in the applications. If there is very little information supplied, the chances of being selected are reduced. You can always send me a PM if you have problems or questions.