Generally speaking, the Wi-Fi frequency will be indicated on the nameplate on the back of the router. You can also check the router manual to confirm the Wi-Fi frequency of the router. You can also enter the background address of the router in the address bar of the browser (generally it will be displayed on the nameplate) ) -> Enter the administrator password to enter the router background -> Click on the wireless settings on the router background page to view the frequency of the router. If your computer or mobile phone is connected to the Wi-Fi of the router, you can also search for query methods in your browser, such as "How to tell if the Wi-Fi connected to my Android phone is 2.4GHz or 5GHz".
If your router only supports 2.4GHz, you can connect to the Wi-Fi directly.
If your router is a dual-band router, which supports both 2.4GHz and 5GHz, please choose to connect to 2.4GHz Wi-Fi.
When your router is a dual-band router, you can usually see two Wi-Fi names in the phone settings -> WLAN, such as Myhome_2.4GHz and Myhome_5GHz.
If your router only supports 5GHz, you may need to replace a router that supports 2.4GHz Wi-Fi.