Can I open the files created in the Trial Version of the software into the full version?

Yes, but only on the same computer that the Trial Version was installed on.

Once you have opened the files in the release version and resaved them, you can then open them on any computer running the program.

If you do have files that were created in the Trial Version that you need to keep and use, it is a good idea to open and save them as soon as possible after installing the release version as any problems or hardware changes to the PC could prevent the program from opening those files from the Trial Version.