American living in Japan – want to begin investing

F, 25. I want to start investing but I don't know where to start. Coming up on my fourth year employed in Japan, and I have the iSpeed app and Rakuten ready to go but haven't bought anything. I heard I'm supposed to avoid any normal Japanese stock basically and just buy US ones because of tax complications. I don't plan on moving back to the USA anytime soon.

Any tips, maybe good resources, would be appreciated.

by enoep