Here are a few resources for learning about Dates with Tableau and a great customer presentation at one of our Think Data Thursday events:
You will find a bunch of great information in the FAQ list but I also recommend reviewing Rody's post and video.
Best of luck
Thanks for the help. The resources are a great help.
Thank you so much for marking the reply. Come back again. There are a lot of wonderful people and resources here to help answer your Tableau questions.