Hi:
This is not an ODS or BASE Reporting question (PRINT, REPORT, TABULATE).
For more help with this particular problem, your best bet is to read the documentation on SAS functions (such as SUBSTR or SCAN or REVERSE), that allow you to manipulate strings. And then to read the documentation on joining tables together. There are several ways to do table lookups and the most efficient way will depend partly on how the data are stored in the extremely big file. How you access the Excel files will depend on the software that is licensed at the site.
To contact Tech Support, go to
http://support.sas.com and in the left hand navigation pane, look for the link entitled "Submit a Problem". (If you also need help with the WAKEUP function or writing a script to execute a SAS program, Tech Support can help you with that, depending on your operating system.)
cynthia