I sometimes use the checkout -b option to create a new branch, check it out at the same time and set up tracking in one command.
checkout -b
In a new environment, I
You should go the submodule dir and run git status.
git status
You may see a lot of files were deleted. You may run
git reset .
git checkout .
git fetch -p
git rm --cached submodules //submoudles is your name
git rm --cached submodules
git submoudle add ....