I need my app to send push notification at a certain time even when the app is off

Hii, so I have designed an app and it's working fine, but now I want to substitute the whenScreen1.initialize block with a block which will get executed at a certain time suppose 12 am, and at 8am, the app will send a push notification about the contains of the ListView2, but during all this activities in the app, the app may or may not stay open. Can anyone suggest me how to achieve this?

You might be interested in the alarmmanager extension to connect to a spreadsheet in the background and send a notification at a given time

Taifun

Yes, I was going through this extension, but unfortunately I cannot afford it, is there any free alternative?

To do all of this

unfortunately not

Taifun

Right, thank you for your time.