Can you be more specific about what you are trying to do? What will the LEDs show? How is your CAN data formatted?
And, of course, have you looked at the examples included with LabVIEW?
EDIT: Also, if you're using NI-CAN (I do not think XNET supports this yet), you can use the "virtual" CAN interfaces 256 and 257, which are internally connected to each other, to test out your code without using any real CAN hardware. Anything sent to 256 is received on 257 and vice versa.
