How can I complete initialisation without Dualshock 4 controller?

Hi,

I’ve been given a PS4 slim with a Nacon controller. It was working but had previous owner’s content on it. I deactivated account then initialised the unit to clear all data. On restarting, it has instructed me to connect Dualshock4 controller by USB and to press the PS button. I’ve connected the Nacon controller and pressed the PS button on this, but this has no effect. Its possible the PS button isn’t working on my controller, but other buttons are bringing up message “cannot display menu now” so I assume connection is working fine. I am guessing that the problem is that this is not a Dualshock4 controller? If so, is there a way to restart without a Dualshock4 controller? I don’t really want to buy another controller.

Many thanks :) Zoe