A good place to start are the LabVIEW examples. From the LabVIEW toolbar, select Help<<Find Examples for the Example Finder dialog box to appear. In the center pane there will be a list of folders, expand Fundamentals<<File Input and Output. There are Write Binary File or Write Text File examples to use as a reference. There is always the Write to Measurement File Express VI as well. Also take a look at the file I/O example from the Sound and Vibration Toolkit (see attached image) if you have access to it. Hopefully this helps!
Regards,
h_baker
National Instruments
Applications Engineer