I downloaded as instructed but the tools folder is empty, please tell me why?

[chunglv-3scorp]

I downloaded git clone https://github.com/Ai-Thinker-Open/AiPi-Open-Kits.git as instructed but the tools folder is empty, please tell me why?

[Selflocking]

The tools/ and toolchain/ directories are submodule directories. You can pull submodules by executing the install.sh script or git submodule update --init.

[chunglv-3scorp]

Thank you