Tested with qmk 0.16.9
You'll need python >= 3.7. Since I was using ubuntu 18.04 at the time, I elected to use a venv.
python -m pip install qmk
qmk setup
Make sure the udev rules get copied over correctly and pay attention to the warnings. You will not be able to flash if the microcontroller can't be detected.
cd <qmk_source>/keyboards/crkbd/keymaps
git clone https://github.com/DevonMorris/crkbd-devo.git
# Alternatively use ssh
Here you have to be careful to select the correct bootloader, which depends on your selected microcontroller. You can find more info here.
For DFU boards (Elite-C V4) use
qmk flash -kb crkbd -km devo -bl dfu-split-left
qmk flash -kb crkbd -km devo -bl dfu-split-right
For Caterina boards (Arduino ProMicro)
qmk flash -kb crkbd -km devo -bl avrdude-split-left
qmk flash -kb crkbd -km devo -bl avrdude-split-right