If you do a search you’ll find various threads about this board and the Mega equivalent.
It seems that the DIP switches can be a bit tricky to master.
It sounds like you’ve overwritten the default code on the ESP8266 portion of the board. I think you need to download and re-flash the original AT firmware to the ESP then use this as a Wi-Fi modem for the Arduino. The code for the Arduino will be the same as if you are using a regular Uno plus ESP-01 Wi-Fi ‘shield’.
Having said that, although it seems that the board you’ve bought is the best of both worlds, it’s actually something that I would never consider using for an IoT project.
If you want to be able to make better choices about suitable hardware then read this:
Pete.