Hi,
There is no dumb question, it is never easy to get started on a new tool :-) If you double-click on the jar file the software should start as shown on the video at the following link:
https://www.screencast.com/t/iDzL79cKzUG
If it does not start please make sure that you have unzipped the folder (working "inside" the zip file does not work), that you have java 64 bits installed, and that the tool is located in a folder where you have writing privileges. If the problem persists, please navigate to the resources/conf folder inside the DenovoGUI folder, there should be a file called startup.log. It will help us identifying the issue.
Hope this helps,
Marc