Begginer in platform.io, need help with programming stm8

I have a lot of experience with arduino ide and i just discovered platform io and i have a few problems with it, i don’t know how to find the examples, select the upload port…, and when i try to program the stm8 it just gives me errors and i dont?know what they even mean, so can someone explain me the basics of platform io and where are the different options located (upload port, baud rate, examples…) and how to fix the errors while programming stm8 and also what are the recommended packages to install and where to use platform io (atom or VScode)

errors in atom:

[.pio\build\stm8sblue\src\main.cpp.rel] Error 1

[.pio\build\stm8sblue\libFrameworkArduinoVariant.lib] Error 309

warnings in atom:

C:\Users-markonjak-.platformio\packages\framework-arduinoststm8\cores\sduino\HardwareSerial.c:38:2: warning: #warning “using uart1 for HardwareSerial”

C:\Users-markonjak-.platformio\packages\framework-arduinoststm8\cores\sduino\WInterrupts.c:73: warning 85: in function attachInterrupt unreferenced function argument : ‘mode’