To clone do the following

For SSH

git clone git@github.com:Sayansree/AUV-ControlStack.git
cd AUV-ControlStack
git submodule update --init --recursive

For HTTPS

git clone https://github.com/Sayansree/AUV-ControlStack.git
cd AUV-ControlStack
git submodule update --init --recursive

Do not edit any submodule directory add other modules in seperate directory inside AUV-ControlStack