Hi Madhu! Welcome to the Tableau Community. A great place to start when you are looking for an answer is to see if anyone has asked the same question before. It is likely that your question has already been asked, or if not you can find resources to help you that are already in the Tableau Community Forums. I did a quick search and found this thread:
There is an extensive thread with this resource from Tableau employee Ted Wasserman marked as the correct answer: http://www.tableausoftware.com/about/blog/2013/2/amazon-redshift-connector-preview
I hope those resources help! Please feel free to reach out with more questions and always feel free to explore! There are 150k people in here who all started as beginners once
Happy New Year!