How can I create callbacks in a C++ class that are referenced to another class?

My code look like this and I'm struggle to understand some concepts, maybe you can help me.

this is the header file

#include <WiFi.h>
class DeviceManager {
    private:
    WiFiEventHandler wifiConnectedHandler = WiFi.onStationModeGotIP(&onWiFiConnected);
    void onWiFiConnected(const WiFiEventStationModeGotIP& evt);
};

I get an error

no suitable constructor exists to convert from "void(DeviceManager::*)(const WiFiEventStationModeGotIP& evt)" to <std::function<void (const WiFiEventStationModeGotIP&)>