How to use AR with Aero in your country?

Hello everyone,
I’m a creator from Vietnam. In Vietnam, when I scan the QR code (the first time using the AR product), I can use the AR experience without having to download the Aero app from the App Store.
However, some of my friends in Korea have to download the app in order to use my AR product.
Could you share how the AR product works when you scan the QR code in your country?
Thank you for your attention!
*I’m referring to the very first time you scan the QR code via Aero.