Samsung wearable

Because this watch is just do nothing other than notification and sport tracking .. its just scam from samsung

Samsung Pay is only available on select phone and watch models. To use Samsung Pay on your smart watch with a non-Samsung phone, you must update to Android 6.0 or higher.

First of all I used many Samsung watches models like, Active2 , watch4 . .

All of them are support Samsung pay and they are pre installed in the watch no need to download.

From any screen in Samsung Watch, press and hold the Back button for 1–2 seconds. If this is your first time opening Samsung Pay, it may take a few seconds for it to start.