When you click Network Activate for this plugin, it will create plugin table only on your main website. also the plugin work only on your main website. and in the sub websites it will show the plugin menu in sidebar however the plugin not work on the sub sites.
Thus, I strongly suggest you to not click Network Activate. Instead you go to particular website dashboard and navigate to plugins menu. There you click activate link for this plugin. So that the plugin work only in that website. If you want to activate the plugin in another sub website, go to that sub website dashboard and do the same.