Download and install ESP-IDF v4.0
export IDF_PATH=/opt/esp32/esp-idf
# Set tools path if needed:
#export IDF_TOOLS_PATH=/opt/esp32
source $IDF_PATH/export.sh
idf.py menuconfig
# Select target:
idf.py set-target esp32s2beta # or esp32
idf.py build
idf.py -p /dev/ttyUSB0 flash monitor