ROS projects such as the Coventry FSAI control code tend to be broken into seperate git repositories each of which handles a specific piece of functionality.
The final project is a 'meta' repository that links to all the seperate repositories and pulls them all together. To do this, we add the seperate repositories as git submodules of the meta repository. This approach makes it much easier to combine repositories written by the Coventry team and repositories provided by 3rd parties (e.g. the driver code for the ZED camera system).
It does however mean that setting up the project is not quite as straight forward as just cloning the meta repository. If you are starting from scratch the easiest option is to clone the meta repository whilst tell it to go and get all of the submodules at the same time.
git clone --recurse-submodules https://github.coventry.ac.uk/ac0745/fsai_ws_training.git
If you have already clones the meta repository and just want to get the submodules.
git submodule update --init --recursive