I can point you to where "the files" are located, but they are not useful outside of the FormsCentral application. You can save any form as a "FormsCentral Design Template" which would have an FCDT file extension and could be re-imported into either the FormsCentral desktop application or web application. The FormsCentral Design Template is saved from the File menu when you have your form open in FormsCentral.
Let me know if that answers your question enough or if you have a need beyond that for the file location.
Sent from my BlackBerry 10 smartphone.