Issues on In-App Messages

I am implementing ACS in my company's project in React Native, I already added Push Notifications and right now I'm trying to implement In-App Messages.

Regarding the documentation, there is not too much to do in Android and iOS, but when I create an In-App Message in the Adobe Campaign Platform the message is marked as Sent, but the device receives nothing.

The documentation generates me lot of confusion, some places mention AEP, other ACS, libraries are not maintained nor released for a long time.

What should I follow exactly? When I talk to the support team, they told me that I should contract an Adobe Consultant to implement this in the app but I have an entire dev team to do this. How I should proceed?