Assuming you're on Wii U, you should've downloaded the Homebrew App Store while installing Aroma. If not, it's on wiiu.hacks.guide. The store is kind of limited right now, mainly having emulators/plugins. For many apps, you'll need the now deprecated Tiramisu environment. ( 1/2 )

This can also be found on the guide. Additionally, some homebrew needs compiled, and can be found on GitHub. Examples being SM64 PC Port, the Ocarina of Time PC port, and Sonic Mania. There's also Virtual Console injections, allowing you to play NES all the way to Wii via an app.

Hopefully this helps. I'd start out by browsing the app store, installing Tiramisu, and trying RetroArch. Good luck! Send me a friend request if you need more help (@bananasplit)