Add documentation

Add documentation for the project

The issue only states 'Add documentation for the project' without specifying what to document or where. A newcomer would need to explore the repository to understand its structure, datasets, and purpose. They should look for existing README files, code comments, and dataset descriptions to identify gaps. 'Done' would be creating or improving project documentation, but the scope is undefined.

由索引模型根据 Issue 内容生成。