Hi there,
Our demo code does two things: it prevents users from editing layouts, scripts, etc. in the demo and it time limits the demo for them. At the same time it shows them a progress bar of how much longer they have to play with the demo.
You'll be able to take advantage of some of this in the file you gave but the progress bar components are not present in the file you have.
Try this on a copy of the file...
Edit the file options to login using the account DEMO and the password DEMO. (Assuming that you haven't removed that account.)
Now change the Demo Date script to use your own versions of the dialogs we present as the user approaches the demo expiration date.
Finally use the Developer Tools in FileMaker Advanced to remove [[Full Access]] access to the files.
Once that access is removed users won't be able to get at your code, and since they'll be running under the DEMO privilege set, the Demo Date script will present warnings to them as they approach the demo expiration (this is currently 10 days, but you can change it in the Demo Date script).
I hope that helps.