Cores not installed

I am using a Nvidia shield tv 2019 and have installed retroarch 1.8.9 and have downloaded and installed some cores but I do not see them on the retroarch mainscreen. I go to the core downloader option and select the core I want to install and a message pops up in the bottom lefthand corner stating latest version already installed, but yet I do not see it installed anywhere… Any help would be appreciated!

For them to show up on the main screen, you have to scan for them (either a regular database scan or a more permissive “manual” scan). Once they’re in a playlist, they should show up on the main screen.

Sorry how do I do that?

Look for “add content” or a plus sign to get to the scanning stuff.