I downloaded Kodi. Now what?

I've searched online. Searched reddit. Don't understand. How do I make it play movies? Most of the options that people say to click on in the sub menu I can't find. And I don't understand the terminology.

I was using cinemaHD before but it doesn't work and won't update. Someone suggested Kodi and said it was really good. Is it like Napster? Is it a browser? What is it? I see a list. TV, Radio, Games, Add-Ons, etc. But I have no idea how to add to the library. And Google doesn't help. Should I look for a more simple option or am I missing something?