How to set link of subreport in main report

Hello Experts,

I am using sap crystal report 2008,

I have created one report where i inserted another report as sub-report, this report is like a child report which should open on click on link given at row level for the particular parameter value which is common between two report.

Now i managed to mapped parameter between two report by setting sub-report as onDemand report but now i don't understand that how to set link to open that sub-report at row level.

Please guide me....

Thanks and Regards..

shekhar