Arduino+ Ethernet and RTC DS3231

Hello, I would like to know how do I program the time for a led via wifi with arduino and a RTC DS3231 module and MIT App Inventor 2 or Thunkable, does anyone have any tips or tutorials to help me?
More precisely, I am making an application in Thunkable, and I need to send a String, or whatever, a command, so that when the arduino receives via WiFi, I can handle the string and configure the times to turn on / off a led , Does anyone have any idea how this would fuck? In my current project, I use the indexOf () function; Is there another way to get App-Arduino data?

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