Please help me understand the process of Appflow

I am looking to subscribe to appflow and I am wondering about the process in which i can submit my app to the appstore/playstore

1- Finish coding my app and testing it through the browser window normally.

2- Link the app’s github to Ionic appflow.

3-???

4- submit the apk/ipa to their respective stores.

What I dont understand is step 3, I know you can click a button to generate an apk/ipa.

and I know how to test an apk file on my android phone,

but since I dont have an iPhone, I would like to test the ipa on an iphone simulator on a mac, is that possible?

I am trying to know if appflow will remove the need of touching xCode/android studio all together, or do I still need to configure them in some way.

also what about certificates? how does that whole process work? I looked over at udemy, and other web courses and couldnt find anything related to appflow which is understandable, youtube isnt helping me either…

Can anyone explain how the process works?