Help with installation on Amazon Fire Stick

Hello
Please can I ask for advice. I’ve installed Kodi 17.0 Beta on to my Amazon Fire Stick today. I followed instructions from an Internet site and used ES File Explorer.
When I open the app, it shows the Kodi symbol and then the next page has the list down the left hand side – movies, TV shows, music etc – but across the majority of the screen it says ‘Your library is currently empty. In order to populate it with your personal media, enter files section, add a media source and configure it. After the source has been added and indexed you will be able to browse your library.’ I then have a choice to enter files section or remove this main menu item.
As is obvious, I know little about this type of thing and I apologise if I am being a bit dim but please can someone tell me what I have done wrong. I’ve looked on YouTube and I expected to see a main screen with the subject headings on a central carousel, from which I could then go into Systems to install the add ons I need.
Thank you in advance for your advice.