You should start with the documentation topic Use summary indexing for increased reporting efficiency in the Knowledge Manager Manual. It explains what summary indexes are, what search commands you use with them, and how to set up the searches. The topics that follow that one explain how to configure summary indexes.
As the procedure I indicated says, it's a good idea to create a separate index specifically for collecting summary data. See http://docs.splunk.com/Documentation/Splunk/5.0.1/Indexer/Setupmultipleindexes for information about creating indexes. I'm not sure where you are running into problems...?
I have gone through the link. But the problem is I have one Indexer server and one search engine. So I am not able to sure where ehat to do i.e. where I have to create the Indexer Summary and all.
Can you plesae help me out!!!