You will need to open a web browser and go to the IP of the WiFiLogger (192.168.4.1 is used only after pressing the setup switch), then select Setup, WiFi Setup,. Change the SSID in Connect to Router with These Settings. I recommend setting a Static IP under the Advanced Settings. My logger is set as a static IP of 192.168.100.12. I launch that address in a browser and do the above steps to make changes.