Hello, friend!
First, you need to log in to the HG8245Q2 WebUI.
Click the WLAN tab, and choose WiFi Coverage Management from the navigation tree on the left. In the right pane, you can specify the SSID for smart Wi-Fi coverage, add the identified external APs to the Wi-Fi network, configure roaming and handover conditions, and disable the identified external APs on the Wi-Fi network.

If you need to set 5 GHz Wi-Fi, you need to set it in the 5G Basic Network Settings tab or the 5G Advanced Network Settings tab on the HG8245Q2.
Note: To configure the device, you need to log in to the device as the device administrator. Because the HG8245Q2 is an ISP series device, you need to contact your ISP to obtain the device administrator account and password.
Thanks!