Onesignal API(push notification) workflow

Can someone please tell me how the onesignal api really works step by step.
I have got it to work on my app Loan. But after update the certificate/profile was invalid. And I am not sure how to update the app without all the certificate getting invalid all the time. Sometime I get this in onesignal image
How do I correct this.
Base likely a update APP tutorial with AND without push notification…

Regarding the Provision profile tutorial it looks like this in the Thunkable tutorial

But like this in Apple

Or am I the wrong place???

I also somehow got a lot crap Identifiers

How can I delete all the UdlaanOld/Udlaan App.???