Hi Preeti
Honestly go to the SAPMarketplace for Installation and Upgrade Guides. Obtain the SAP GRC 5.3 Configuration Guide and it steps you through everything. This guide is quite comprehensive on the configuration and tips/recommendations.
You need to define you connectors (and logical systems if you are using them) and upload your authorisation text files, etc. You then go to Rule Architect to define your functions, risk and rule sets
Regards
Colleen