In a licensed node you have and acceptance and a production environment. The accp environment is there so that you can test all your changes to see if everything is ok. Most of the time an external client also needs to approve this version. After all test is done you can then move that version to production. Always create a backup first before doing the transport because you never know what might go wrong (like unable to start for instance allthough I have never experienced that myself).If an environment does not start check the logs of that environment. It will give you a clue on the reason.
And you do not need the web modeler for the creation of packages. All can be done from Studio Pro.
Check this learning path for more details: https://gettingstarted.mendixcloud.com/link/module/226/lecture/1769
And for the puplishing part check these docs: https://docs.mendix.com/howto/mobile/publishing-a-mendix-hybrid-mobile-app-in-mobile-app-stores