I want to start and implement push notification service for my react native android application. Can someone help me to find out the prerequisite and and latter steps for the steps.
Are you talking about a demo version of Adobe Campaign standard or does your organization already has licensed version ? There are 2 ways of creating android push notification.
1 - Configuring a mobile application using SDK V4
2 - Configuring a mobile application using Adobe Experience Platform SDKs
If you are not able to access Mobile app channel in ACS than it might not be enabled for your instance and needs to be done but firstly depends on if you have a demo instance or referring to your organization`s instance.