sudo -u postgres psql -e --command "CREATE USER odoo WITH SUPERUSER"

or

sudo -u postgres createuser -s $USER
createdb $USER

git clone -b 14.0 https://github.com/escodoo/odoo-lab

cd odoo-lab
git submodule update --init --recursive

python -m venv .venv
source ./.venv/bin/activate

pip install setuptools wheel

cd odoo/src
pip install -r requirements.txt

cd ../external-src/oca
../../../install-requirements.sh

./odoo/src/odoo-bin -c odoo.conf -d odoo_lab