How does the touch function work

[EthanGe77]

I saw touch2-5 touch7-9 on the layout image. not quite sure how to use them

[lewisxhe]

There are examples in Arduino esp. Just write the code and touch the IO port after running. You will see the response.
https://github.com/espressif/arduino-esp32/tree/master/libraries/ESP32/examples/Touch

[bbogdanmircea]

In the original code, there are 2 Button 2 instances attached to pins 35 and 0, but these pins are not on the board. How or where should I connect to these pins?

[m-stefanski]

For those who will stumble upon this question.

GPIO 0 and 35 are physical buttons that have to be clicked, TOUCH GPIOs are supposed to be, well, touched. Change of voltage upon touching gpio with a finger on the pin gets detected.