How to fill Movie section in latest version

I just installed the latest version of Kodi, but I have a serious problem to use it. I do not understand how to fill the library . I go to the main menu and click on Movie . Then I move to the right panel and I click on Enter files section. I select one of my sources, that is, a Synology NAS. Then I select my video folder but at this point I have no idea how to tell Kodi that it has to use that folder to fill the library. Help appreciated.