How do I connect the AC1200 extender to a hidden WiFi network?

Log in to the extender at www.mywifiext.net, select Settings > Connect to Existing Network, and choose 'Manually input my wireless SSID.' Enter the name of your hidden 2.4 GHz network, select the security type from the dropdown menu, and enter your network key or passphrase. Repeat the process for your 5 GHz network if applicable. Wait about two minutes for the extender to establish the connection.