• Install ML-Agents Release 9 in following URL and put ml-agents-release_9 folder in Unity project. https://github.com/Unity-Technologies/ml-agents/releases/tag/release_9

• In Anaconda Prompt:

conda create -n mlagents9 python=3.7
cd ml-agents-release_9
pip install -e ./ml-agents-envs
pip install -e ./ml-agents

1. Clone this repository.
2. In Unity Editor, Select Window> Package Manager > + > Add package from git URL... and add https://github.com/Cysharp/UniTask.git?path=src/UniTask/Assets/Plugins/UniTask.
3. In Unity Editor, Select Window> Package Manager > + > Add package from disk... and add package.json in ml-agents-release_9/com.unity.ml-agents folder.
4. Change directory to ml-agents-release_9 and Run:

mlagents-learn config/HelloToio.yaml --run-id=HelloToio-ppo-1 --time-scale=1

• pip install -e ./mlagents had a error ERROR: After October 2020 you may....

pip install -e ./ml-agents --use-feature=2020-resolver

(reference: https://note.com/npaka/n/n92580a746f2d)

• TensorFlow could not import. This problem has been solved for following command.

pip install --upgrade tensorflow==2.0.0