There are a number of tools to extract data? What application are you working with? HR/Payroll, GL, PL, etc?
Infinium HR comes with its own Query 2000 tool, although it can be rather cumbersome. Else there is AS 400 query, if you have access - but its fast and straight forward. Does your company have Cognos, ShowCase or any other application / tool?
If you are not familiar with the files/fields to access, each application's documentation comes with a file/field directory (i.e. with HR/Payroll HCM, it is HCM_12.pdf in their Navigator documentation.
Our company specializes with the Infinium applications and I can walk you through some areas to give you a head start.
If you'd like additional information, please feel free to call me at 856-691-4773.