To practice, you can do as direction at Bài 26 - Huấn luyện YOLO darknet trên google colab

Or another simple way opens darknetGoogleColab.ipynb file and start run from item 3.2. Enable GPU trên google colab.

After you understand how does darknet work. You could train model on your own data and reserve it for your private task.

Before practice, i recommend you understand YOLO algorithm at Bài 25 - YOLO You Only Look Once