Hi technical,
Please refer below for getting more familar with DLP. It will help you to inderstand and clear your some doubts. I can understand that your new to this product and wanted to clear some doubts.
https://www-secure.symantec.com/connect/articles/symantec-dlp-policy-note-beginners
https://www-secure.symantec.com/connect/articles/what-protection-does-symantec-dlp-provide-note-beginners-part-2
https://www-secure.symantec.com/connect/forums/demo-dlp-video-tutorials-documentation-how-tos