How can copyrighters with no experience get jobs in advertising?
Start answering on Quora
Write blogs about modes of Advertising
Write blogs about the advertisement of various brands which have been viral on the internet
You can be active in showing your perspective via nice writeups on LinkedIn like platforms
Do an internship in Creative Agency
Eventually, this will become your experience.
Also you can begin with Freelance model / Pay if you Like a model.
There are lot of groups for Content and Graphics and various portals which can bring you projects for developing a profile.