STM32 Blue Pill bootloader for Arduino #4

How to enter the bootloader to program Blue Pill STM32F103C8T6 via USB port with Arduino IDE
Bootloader: github.com/rog...
stm32cube: www.st.com/en/...
Connection to the Arduino board: github.com/stm...
more info in the pdf file: github.com/rg4...
Material:
Blue Pill (select "original"): s.click.aliexp...
STlink programmer: s.click.aliexp...
USB/232 converter (for programming directly without STlink): s.click.aliexp...