I have a GE learning remote
Can I hook it up to AppleTV? I don't see where to do it.
Without knowing the exact model of remote, it's hard to say. Chances are it is a infrared remote.
Go into Settings > Remotes and Devices > Learn Remote
See this support article for more information: https://support.apple.com/guide/tv/use-other-remotes-atvb0410f604/tvos
Also this: https://www.imore.com/how-use-universal-remote-apple-tv