Asking for advices regarding resources

Hello everyone, I am a new beginner who potentially wants to contribute to Hugging’s Transformer open source project. So, I would like to first familarize with PyTorch, Jax, and TensorFlow.
Can anyone recommend me any online resources that I can study to work on PyTorch, Jax, and TensorFlow projects that can be helpful for familiarizing before contributing to Hugging’s Transformer open source project?