Hi,

This has nothing to do with a “backup”.
You want to deploy your Studio project into a demo server? If so, download the JAR file and, as you guessed, deploy it to nxserver/plugins (or nxserver/bundles). Then start your demo server.

If you want to benefit from the Admin Center features (package management, update, …), then you must register your demo server with your Connect account, installing your Studio project as an automatically managed package instead of a manually managed simple JAR file.

If you want to “freeze” the current status of your project, then you're looking for the “release” feature in the “Settings & Versioning” menu.

Regards