Every couple months, I’ll clone a repo with submodules and have to go re-learn how to clone the submodules from this guide.

For future me, who’s forgotten again - how to clone a submodule in a repository you’ve already pulled:

git submodule init
git submodule update

If you have enough foresight - how to download submodules at the same time you clone the main repository:

git clone --recurse-submodules <your-repository>