Push notification Proximity Beacons iOS/Android

My team is trying to send push notification to both iOS and Android device, when the user is in the Beacon range after a certain time range, for example 10 mins.
Currently, I have installed proximity in our iOS Xcode and Android studio. I can see the range is working through Log and LogCat.
Now I am wondering how do I build the push notification functionality.

I saw there is an option “Beacon with notification” in Choose your App in Cloud.

But apparently we are building our own apps. Want to push the notification when the user is around the beacon.

Thank you!