Yes, you can use Plume with your existing router. Download the app and follow instructions to set up Plume with your router. 

Please make sure to turn off the Wi-Fi on your router after the setup to allow Plume to efficiently manage your home Wi-Fi. 

Please note that Plume will not work as an extender of your existing Wi-Fi network. Setting up Plume requires you to set up a new Wi-Fi network.