Default Year and Month Values for Value Prompts based off of cube data

[COGGI]

Hi ---> I need to run the report for default Year and Month values. The report is a RS report based off of cube. I tried all options available online like Macros and all the stuff but i was not able to figure it out. Can some please let me know the step by step process along with the Data Items and Measures that need to created and the OLAP Functions that need to used to accomplish. As much in Detail as possible would of great help. As i tried each and every option that i know and still have issues.