How to install cordova crosswalk plugin manually in existing Android Project

Question

I need to integrate crosswalk plugin in my Android project to support webview of older versions in android. I'm developing in Android Studio and tried to follow the instructions in this link: https://crosswalk-project.org/documentation/cordova.html

My Android project is separated from the cordova base project so obviously I got this message:

"Error: Current working directory is not a Cordova-based project."

My current app is working without the base cordova project and I need to install the plugin manually.