There are three different forums which are more appropriate to this question, but first
you have to decide how you want to access the FGDB -- If it's with Python, head on
over to the Python forum; if it's with C#/.Net or Java, then ArcObjects SDKs is your
destination; and if it's outside of ArcGIS with C++, then the FGDB API is for you. Any
way you choose, it would probably be wise to try using the product (reviewing the
documentation and trying to use samples), so you can ask a more specific question.