It has been preflashed with the correct firmware and you can just connect it up and set up your wifi settings.

Download CCGMS 2019 here : https://csdb.dk/release/?id=173065

and then follow these steps : Load CCGMS 2019, select User Port, and select 300 baud Go back to terminal mode Power on the device if using external power and hit enter A menu should show up from the modem letting you know it’s alive! Hit F8 to go to Ascii mode (Anscii mode) and enter your ssid and password with the following terminal commands: at$ssid=ssid and at$pass=password F8 to go back to the Graphics terminal and type atc1 to connect. This may take a few attempts to connect. Use the commands at&p0 and at&k1 . Without doing these 9600 baud will lock up your c64 Change the baud rate by using the command at$sb=9600 Go back to the Terminal F7 Menu and select Up9600 Baud / 9600 Baud Go back to the terminal, and you should be able to see at and ok reponses. * Use at&w to write these settings to the esp8266. All done. Now your settings should be set every time you boot CCGMS 2017!