This plugin is delivered with the NopAdvance Core plugin on which this plugin is dependent. You need to install the plugin using the plugin installation guide provided here

Once the plugin has been installed, you will see the menu under NopAdvance > Plugins > Smart slider plugin in your nopCommerce admin menu, similar to the below image.

Click on the Configure menu item from the Smart slider plugin menu as displayed above and you will be redirected to the plugin Configuration page.