First, The "Getting Started with IBM Tivoli Monitoring on Distributed Environments" PDF contains great information on ITM 6.1, and it is applicable to all of the 6.x versions:
http://www.redbooks.ibm.com/redbooks/pdfs/sg247143.pdf
Chapter 4 specifically goes over the Tivoli Data Warehouse, including the DB2 table and column names. Specifically, look at section 4.2.4 for descriptions of the different table names.
The tricky part in DB2 is that the table and column names are all case sensitive, which means you need to enclose the table name inside double-quotes in your sql statement. For example, you would use this SQL statement to get percent processor time for all processes for all servers:
select "%_Processor_Time","Process_Name" from "NT_Process"
If you want to see data that hasn't yet made it to the TDW, then you need to use the krarloff command described here:
