To remove the Adobe watermark from the tryout project file, you open it in the purchased version and then do either of the following
1. Timeline Menu/Delete Rendered Files and then render the Timeline content
2. Do nothing...for some of us the Adobe watermark from the tryout project file automatically disappeared when opened in the purchased product.
You cannot remove the Adobe watermark from an export of the tryout program, be it export to file saved to the computer hard drive or burn to.
Any questions or need clarification on the above, please ask.