On the D-Link home page, navigate to the Settings tab and choose "Wireless."
In the 2.4GHz section, configure Wi-Fi Name (SSID) as <xxx>-2.4G, with xxx denoting the Wi-Fi name.
for the 5GHz section, set Wi-Fi Name (SSID) to <xxx>-5G, with xxx denoting the Wi-Fi name.
The final step is to save the settings.
Once completed, the new Wi-Fi names will be visible on your mobile phone's Wi-Fi settings page.
Note: After altering the Wi-Fi names, reconnect devices to this wireless router. The password remains the same unless changed.