Copy the file .github/workflows/main.yml into the .github/workflows folder of your repo and name it, e.g., flexbe_ci.yml.
Substitute
run: |
ln -s $GITHUB_WORKSPACE ~/flexbe_ci
source ~/flexbe_ci/setup.bash $ROS_DISTRO
by
run: |
git clone -b $BRANCH_NAME https://github.com/FlexBE/flexbe_ci.git ~/flexbe_ci
source ~/flexbe_ci/setup.bash $ROS_DISTRO