It should be right in that base folder. It's titled "rmoffice-4.3.20.jar" and in the same folder where "howto-launch-rmoffice.txt" and the icons, readme, and templates folder are located.
If you don't see it, either:
* You have antivirus software that is blocking the creation of an executable file, or
* Windows is not showing you the .jar extension so you simply aren't noticing it is the file you are looking for.
Regarding that latter possibility, hiding extensions is what Windows does by default, because they assume you can't be trusted with that information. So:
* In Windows 10, click View on the ribbon and check the box for "File name extensions"
* In Windows 7, tap the alt key to show the menu, then go to Tools/File Options, then go to the View tab and uncheck the box for "Hide extensions for known file types."