Hi again,
if you have galaxy active 2 watch, then you use the galaxy watch designer or studio program for making watchfaces.
A) if you want to make custom shortcut, you need to know the ID of the app on the watch. It looks usually like this: com.samsung.stopwatch-wc1
Check this topic.
B) if you do not know the ID, or you simply want to be able to asign any app (for example some new that you install in future) to the button, the app-switcher makes it customizable from the watch. By double tap the watch offers list of installed apps and after selecting one, it will open by single tap ever since, until changed again by double tap.
