Phone app: Notifications not working, customize the notification sound

I just upgraded my phone and the notifications are not working on the new device.  

How do I:
1. Get notifications working again?
2. Customize the notification sound so that it's not the standard/default notification sound?

Background:
I installed the SimpliSafe app on a Samsung Note 9.
When I go to settings / notifications / SimpliSafe I have the following options:
 APP NOTIFICATIONS
 ON/OFF (this enables or disable ALL notifications, so I have it set to ON)
 App icon badges  on/off  (I have this set to ON)
 Downloads (make sound) on/off  (I have this set to OFF since I don't have any cameras associated with my system).

Alternatively, if I open the SimpliSafe app, choose menu / settings / Alerts & Notifications / Push Notifications, I have the following options:
 Alarm (this box is checked)
 Activity
 Error

Please advise on the above two questions.  Thank you!