This step cover you how to setting Login with Facebook, to create Facebook App check it first https://doc-oreo.rnlab.io/docs/v1/web-config#config-facebook-app-id-and-app-secret
Add your development and release key hashes To ensure the authenticity of the interactions between your app and Facebook, you need to supply us with the Android key hash for your development environment. If your app has already been published, you should add your release key hash too.
You'll have a unique development key hash for each Android development environment. To generate a development key hash, on Mac, run the following command:
keytool -exportcert -alias androiddebugkey -keystore ~/.android/debug.keystore | openssl sha1 -binary | openssl base64
On Windows, run this command:
keytool -exportcert -alias androiddebugkey -keystore %HOMEPATH%\.android\debug.keystore | openssl sha1 -binary | openssl base64
This command will generate a 28-character key hash unique to your development environment. Copy and paste it into the field below. You will need to provide a development key hash for the development environment of each person who works on your app.
If your app has already been published, you should also add a hash of your release key.
Android apps must be digitally signed with a release key before you can upload them to the store. To generate a hash of your release key, run the following command on Mac or Windows substituting your release key alias and the path to your keystore:
keytool -exportcert -alias YOUR_RELEASE_KEY_ALIAS -keystore YOUR_RELEASE_KEY_PATH | openssl sha1 -binary | openssl base64
This will generate a 28-character string that you should copy and paste into the field below. Also, see the Android documentation for signing your apps.