Hello Kishore Kumar,
The first that you have to do is generate and stack.xml file for your system with SAP Solution Manager.
Here you select your system and what update you can/want to do.
When you generate your stack.xml, SAP Solution Manager add all software need for your update in your basket (you have to aprove the software with SM).
Now you must download the last update of SUM software for your platform from the Sap Support Portal.
Here you can download helpful guides to use this tool.
When you run SUM tool, in your firsts steps, you will add the stack.xml file (in the same directory of the update software), and you will can continue with the update.
It is ver important read and understand the related notes of your EHP and SUM.
I hope that this can help you! Good luck!