Okay - this is rather a simple google search. I searched for 'SSRS dynamic data source' and the first item in this list is an article from this site.
The first page of results has a lot of results outlining how to set this up.
Jeffrey Williams
“We are all faced with a series of great opportunities brilliantly disguised as impossible situations.”
― Charles R. Swindoll
How to post questions to get better answers faster
Managing Transaction Logs