IMPORTANT: Follow this step after you have done all of the previous steps
Make the signing certificate
First, let's make a key - certificate that we will use for debug and release signing. So we don't make two key files.
The official documented why by React Native is to make the keystore via command line. But since this is a bit complex, we will suggest the following steps.
Open android studio
Make new app, doesn't matter what you enter.
Go to Build->Generate Signed Bundle / APK, click next
Select Android App Bundle or APK ( it is the same ) , click next
Click on "Create new" to create new keystore
For keystore path, select your project folder, and then go in android/app/production.keystore
For passwords, and aliases use your values. Remember them.
After you have made the keystore, open android/app/build.gradle and around line 155, change the values of the release element with the values you have.
For reference, look into this video
Run the app on an emulator or Android device (device recommended)
To run the app on Android Emulator, you will first need to manually start the android Emulator via Android Studio. You should already have to download the Android Studio in step 1 - the Environment setup. In that guide, there is also really good information on how to prepare a real device or starting the Android Emulator. Search for "Preparing the Android device" in the React native docs.
Once you have the emulator started or a device connected via USB ( and developer mode enabled and USB debugging allowed ), you should be able to start the app on the. To do that, run the following command at the root of the project.
npm run android
After this, you should see the app running on your emulator or connected device.