How do you start working on an already functioning project without starting from scratch?

When working with an already functioning Python project, I usually start with the following steps:

1. Studying documentation and code — understanding the architecture, main modules, and dependencies.
2. Setting up the environment — cloning the repository, installing necessary libraries via requirements.txt or Pipfile.
3. Running the project locally — checking that the project works, examining logs and behavior.
4. Understanding business logic — figuring out what tasks the project solves, what key functions it has.
5. Communicating with the team — clarifying details, receiving recommendations and advice.

This approach helps to quickly get into the project without the need to start from scratch.