Pico SDK is set in the env: PICO_SDK_PATH to the https://github.com/raspberrypi/pico-sdk/ repo

FreeRTOS-Kernel is set in the env: FREERTOS_KERNEL_PATH to the https://github.com/FreeRTOS/FreeRTOS-Kernel repo

arm-none-eabi toolchain is installed to: /opt/toolchains/arm-gnu-toolchain-x86_64-arm-none-eabi/bin/arm-none-eabi-gcc or is installed via sudo apt install gcc-arm-none-eabi as indicated in the Pico SDK readme

Make sure the CMake extension is installed, and run the build task when you wish, or manually build the binary:

$ mkdir build && cd build
$ cmake ..
$ make

The resulting .uf2 in build/src/ can be dragged and dropped into the mounted tiny2040 in bootloader mode.