The Development Server option in the Unplugged Settings on the device turns on an http server on the device and displays a URL. Entering that URL in to Chrome or Safari on another machine on the same network will allow you to connect to Unplugged on the device and navigate the databases as if you were on the device.
This is used for testing and troubleshooting purposes because browser tools can be invoked, such as debuggers, to check that the page is performing as expected or tracking down issues.
There is no other set up required on the Unplugged side and if the browser can't connect to the device then it likely to be a browser settings, firewall or DNS issue preventing access to 192.168.x.x addresses.
Using browsers other than Chrome or Safari is unlikely to work as expected due to their rendering of XPages.