Troy,
you can get a lot more information from the Ralphs latest book on the ETL toolkit. Unfortunately and general ETL discussion is, by necessity, not tool specific.
Also, if you check out my company web site
www.instantbi.com you will see we have released a 'mapping spreadsheet' that will help you understand some basics of mappings from staging area to target......look under downloads->beta software->IDW MG Beta...
There is also a presentation about it as well.....
We have also now released a beta for software that generates ETL directly from the mapping spreadsheet (though not in DataStage).
I believe this invention of being able to do all mappings in a spreadsheet will revolutionise ETL development because we all need to write the mappings somewhere and we usually do that in a spreadsheet...then we code it into a tool like DS.
We are currently doing a large and complex EDW and we are generating all ETL code directly from our mapping spreadsheet.....not bad!!