Approach to create report using SSRS with sub-reports

Hi,

I have to create one Main report with 2 parameters, 1) Universe 2) Client in SSRS

Now here is the scenario,  There are total 6 Universe and each Universe has 10 Clients. Each combination has different number of fields so I am creating 10*6= 60 reports for each client-universe combination. Now I want to create one main report in which when user pass values for client and universe it will populate that particular report. I am assuming I can do that using sub-reportbut I am not able to set the property of that main report to pull that particular report based on client and universe value I/user passed in parameter. 

I need step to set up my main report to pull sub-reports based on these 2 parameters. I am new to SSRS. I am very thankful for help and appreciate for you suggestions.

Thanks in advance.

Vicky