You can use simulation mode. In VTPro with the file open.. Select Edit/Project Properties/Compile/Check Simulation mode/Compile the file by selecting File/Compile Project.

A folder is created with a bunch of files. Double click the xpanel.exe file. You can only really demo a page flipped file so if your using subpages and joins to drive them you wont see any of that working.

As for themes.. I keep saying it.. they dont exist in the way your thinking. Any themes will be plain vtpro files with a vtt extension. I have yet to see a theme from anyone anywhere ever that you can plug in and have it autogenerate in the way that Destiny does.