I want to do a clock countdown and I want to send a notification
I agree with @Peter . You have to ask a detailed question.
I will give you one pointer. When thinking clock down, think clock up. The clock on the device only goes up. So if you want a five minute counter down, you set it to watch when the device time has increased 5 minutes.
I hope that gives you a good start.
try to use the firebase for your notifications, to discount you can use a timer to check the time including a formula of elapsed time + saved time - current time / 60.
I hope it will help you in beginning your practices.
IwantodoaclockcountdownandIwanttosendanotification.aia (15.0 KB)
this is the way