Reminders for notes

I'm creating an application for writing notes and I would like to make reminders in it. A notification appears in the application, you can set a reminder time, and after this time a notification will appear on the badge. I know that this will require an extension, so please replace the badge with something (I can handle it myself). please reply.

You already aaked something very similar here

You also can try the alarmmanager extension


What is the download link for this extension?

as it is a paid extension you first pay and then get a download link...
just read the large green box on the bottom of this page App Inventor Extensions: Alarm Manager | Pura Vida Apps


Is there any similar extension without paying?

There is a basic alarm extension here [FREE] Alarm Extension

You get what you pay for. .