My boss wants to give me a project in IBM Data Stage to work on it. So I've started do know and understand DataStage. Which links do you recommend to download. And do you know any site that has a good free tutorial?
If your boss really wants you to learn DataStage, get onto a proper (paid) training class with your boss paying.
There is no free tutorial worth having. I have 30+ years experience with DataStage and its precursors, and have been a trainer all that time. (IBM only acquired it in 2005)