How do you use Serial (115200 baud rate)?

Hi Guys!!! how to use Serial (115200 baud rate) (read as strings using "\n") and put an button on screen on runtime
please help

9600 baud is more realistic and is a common default.

Im on ESP32

There are a number of ESP32 Guides by Power User Juan:

https://community.appinventor.mit.edu/search?q=ESP32%20%23tutorials-and-guides