On the configuration page, select the "WiFi" tab.
The first entry on this page is the SSID and Password of the access point (default RDZsonde/RDZsonde).
If you want to connect rdzTTGOsonde to an existing WiFi network, you can add the SSID and password of additional WiFi networks here (only simple authentication as used by most home routers is supported, no enterprise authentication or captive portals). If you enter multiple networks, rdzTTGOsonde will connect to the first detected network (in WiFi debug mode) or to the network with best RSSI (in WiFi background mode).
After changing WiFi configuration, you have to reboot the device. The IP address obtained by DHCP will be shown on the screen. Use this IP address (instead of 192.168.4.1), if your rdzTTGOsonde is connected to an existing WiFi network.