Clone a repo with submodules

git clone --recursive https://github.com/repo/repo.git

or if you forgot the –recursive

git clone https://github.com/repo/repo.git
git submodule update --remote --recursive

Add a submodule

git submodule add https://github.com/repo/repo.git path/to/module

Remove a submodule

git submodule deinit path/to/module -f
git rm path/to/module -r
git commit -m "Remove submodule"
git push