The step-by-step guides on how to install and enable Jet Basics NAV can be found at the preceding website.
Make sure that you use the guide that's appropriate for your version. Basically, there's a version prior to Microsoft Dynamics NAV 2013 and a version that's for Microsoft Dynamics NAV 2013 and above. The following screenshot shows the Jet Basics NAV installed as an Excel Add-in:
The following screenshot shows the Jet Reports in action: