So - my question is - how do you expect the 2nd form to submit to the DB? It is not based off the DB, so there is no option to submit it....Your first form is based off the database. So it does submit to the database. I mean, you can add code to submit to a DB.... but I'm guessing that isn't your intent.
Conditional formatting is part of InfoPath. Click on the repeating section in the form and add a rule that is a formatting rule.
DS is just shorthand for data source.