Buy plenty, a supermarket chain, had successfully

Buy plenty, a supermarket chain, had successfully implemented an in-store promotional campaign based on video messages flashed on a large screen.

What is the meaning of the above sentence?

“Buy Plenty” = the name of the supermarket chain. As it is a proper noun, each word should begin with a capital letter.

To promote various products the chain tried showing advertising videos on a large screen inside the store.

The campaign was successful.