Added a step to android secure storage setup (#103)

Author: BellringerQuinn

sdk/unity/onboard/recovering-sessions.mdx

@@ -33,6 +33,8 @@ On Web builds, we leverage [IndexedDB](https://developer.mozilla.org/en-US/docs/
 
 On Android builds, we leverage the [Android Keystore](https://developer.android.com/privacy-and-security/keystore).
 
+The first step is to import the `AndroidKeyBridge.java` plugin into your Assets folder. This is most easily done via Samples in the package manager - simply import the sample titled `Android Secure Storage`.
+
 Our Keystore plugin for Unity (included in the SDK) requires a Custom Main Gradle Template. Please navigate to your Project Settings, then under `Player > Publishing Settings` enable `Custom Main Gradle Template`. This will create a file `Assets/Plugins/Android/mainTemplate.gradle` (or similar, the editor will show you the path) if you don't have one already. Here is an example `mainTemplate.gradle` file; please copy/paste this (or incorporate into your existing file).
 
 ```