Please see the copyright office website at http://copyright.gov.in/Default.aspx
Read the copyright handbook and FAQs available on the website. If you are not pressed for time, read the copyright act, which will be the best!
You may focus your lecture on subject matter of copyright, ownership, duration, rights of copyright holder, infringement and statutory exemptions. You may tailor made your lecture according to the level of audience.
I wish you good luck for your lecture!