Hi Pawan,
You need to backup your configurations if you have made any changes to particular files e.g any sbo file change or properties file change for SSO. These will be overwritten during the patch install.
Unfortunately I dont have snapshots but it should be fairly straightforward. You can refer the Install Guide for detailed steps.http://service.sap.com/~sapidb/012002523100003243042014E/sbo41sp3_patch_update_en.pdf
Hope it helps.
Regards
Chinmaya
