This documentation may help you: https://world.mendix.com/pages/releaseview.action?pageId=18612412
We use Apache Cordova/PhoneGap to create a wrapper around the mobile app. It's relatively straight forward, you simply point it at your mendix app hosted on your machine or cloud and it works. Obviously you do need to download and setup the PhoneGap environment using XCode or Google Android SDK.
Regards