The standalone version of eHour is installed using a installer, specific to your operation system.
At http://ehour.nl/download/download.phtml there is a separate 32-bit and 64-bit eHour download for Windows. The version must match the Java environment installed - when you installed a 32-bit Java environment on a 64-bit Windows OS you need to download the 32-bit eHour download. Nowadays it's most likely that you run a 64-bit version of Java, Windows and thus eHour.
Using the installer, eHour will be installed as a service.The advantage of running eHour as a service versus starting it manually:
automated recovery of eHour after a server restart
reduced risk of shutting down eHour by accident
To be able to install eHour as a service, the installer needs administrator permissions.
When the installer finishes eHour is started automatically and accessible with your browser on http://localhost:8000/