Hi Saravanan,
a good starting point would be to us this link - https://s1.ariba.com/Help/Main/aw?awh=r&dard=1 and start reading product documentation.
If you are part of the implementation team, you would have access to the website ( this is HTTPS ), here you would find the documents like
1.Ariba - Procurement Solutions Integration Guide for SAP
2. Ariba_SaaS_Technical_White_Paper_January_2012_copy_(2)
3. Ariba - Common Data Import and Administration Guide
4. 97942_5800_ReleaseGuide
5. 12s-ssp-release-guide
6. Data dictionary - this is a source of all ariba files ( 290 in total, plus some more which are not pat of official data dictionary, but would be required for Ariba- eg: SuplierID_Delete.csv or supplier_Delete.csv, and other 'helper files' which would be required, based on the 'custom changes' you would do
Google it if you do not have access to the secure site.
Please let me know if i have answered your questions:) .
Regards
Rahul