Pushover doesn't have to be complicated.
Keep in mind that when you sign up for Pushover it provides you with a pushover "email" that you cannot log in and use for anything except to use it to send push notifications to.
So you can simply go into the alerts in BI and tell it to send an email instead of a push and you are getting your push notifications from the Pushover app.
Don't get me wrong, the Pushover API process that
@jaydeel discusses adds way more functionality and customization, but if you are just looking for a simple push and a quick setup, the pushover email option is simple to setup.
Prior to pushover, I was doing the SMS method and once mobile providers tightened their spam algorithms and my texts would be delayed and what not, I simply went the pushover email route and was simply replacing my SMS number with the pushover email.
Quick, simple, gets the job done. Signing up for Pushover was like a minute LOL.
So many of my cameras still use the pushover email option, but I have gone to the API process for a few of my key cameras that I wanted the more customization that the API provides.